reproduction

1. The act of reproducing or the condition or process of being reproduced.
2. Something reproduced, especially in the faithfulness of its resemblance to the form and elements of the original: a fine reproduction of a painting by Matisse.
3. Biology. The sexual or asexual process by which organisms generate new individuals of the same kind; procreation.

Concept

The term reproduction encompasses the entire variety of means by which plants and animals produce offspring. Reproductive processes fall into two broad groupings: sexual and asexual, the latter being the means by which bacteria and algae reproduce. Many plants reproduce sexually by means of pollination, and some plants alternate between sexual and asexual forms of reproduction. Other creatures, such as bees and ants, reproduce through a form of reproduction called parthenogenesis, which is neither fully sexual nor asexual.

How It Works

Asexual Reproduction

Asexual reproduction involves only one organism, as opposed to two in sexual reproduction. It occurs when a single cell divides to form two daughter cells that are genetically identical to the parent cell. This process is known as fission, and it may take the form either of binary fission, in which two new cells are produced, or multiple fission, which results in the creation of many new cells. Since there is no fusion of two different cells, the daughter cells produced by asexual reproduction are genetically identical to the parent cell. Asexual reproduction usually takes place by mitosis, a process during which the chromosomes in a cell's nucleus are duplicated before cell division. (Mitosis, chromosomes, and many other topics referred to in this essay are discussed in considerably more detail in Genetics.)

Whereas sexual reproduction is extremely complex—and human sexual reproduction is much more so, freighted as it is with degrees of meaning that go far beyond mere biology—asexual reproduction is a fairly simple, cellular process. Of course, nothing in nature is really simple, and, in fact, the dividing and replication of DNA (deoxyribonucleic acid, the genetic blueprint material found in each cell) is a complicated subject; however, that subject, too, is discussed in the essay Genetics. DNA is located at the cell nucleus, which is the cell's control center, and the nucleus is the first part of the cell to divide in asexual reproduction. After the nucleus splits, the cytoplasm, or the cellular material external to the nucleus, then divides. The result is the formation of two new daughter cells whose nuclei have the same number and kind of chromosomes as the parent.

The adaptive advantage of asexual reproduction is that organisms can reproduce quickly and by doing so colonize favorable environments rapidly. (See Evolution for more about the importance of adaptation and environment in shaping species.) For example, some bacteria can double their numbers every 20 minutes. In addition to bacteria, which are discussed in more detail in Infection, other life-forms that reproduce asexu-ally include protozoa (varieties of which are examined in Parasites and Parasitology), blue-green algae, yeast, dandelions, and flatworms.

Sexual Reproduction

Sexual reproduction involves the union of two organisms rather than the splitting of one. Like asexual reproduction, it is a process that takes place at the cellular level. In sexual reproduction it is not binary fission that occurs, but the fusion of two cells. Nor are the two cells identical; rather, the cells—known as gametes—can be identified as either male or female according to the makeup of their chromosomes. The male gamete is called a sperm cell, and the female gamete is termed an egg cell. In sexual reproduction, the sperm cell fuses, or bonds, with the egg cell to produce a cell that is genetically different from either of the parent cells. This process of fusion is known as fertilization, and the fertilized egg is called a zygote. Gametes are produced in the male testes and female ovaries by a splitting process called meiosis. (Meiosis and other terms mentioned briefly in these paragraphs are discussed in much more detail in Genetics.)

Meiosis produces haploid cells, or ones that have half the number of chromosomes as are in a normal cell for that species. When the haploid sperm and egg cells fuse at fertilization, however, the chromosomes from both combine, so that the normal number of chromosomes appears in the zygote. The shuffling of the parents' genetic material that happens during meiosis allows for new gene combinations in offspring that account for variations between offspring (which is why you don't look just like your siblings) and which, over time, can improve a species' chances of survival.

Real-Life Applications

Examples of Asexual Reproduction

As we noted earlier, bacteria, blue-green algae, most protozoa, yeast, and flatworms all reproduce asexually, as do mosses and starfish. (The last actually reproduce both sexually and asexually by means of alternation of generations, discussed later.) The products of asexual reproduction are known as clones—an example of the fact, discussed in Genetic Engineering, that cloning and the concept of clones are not as new as one might imagine. (See that essay for much more about artificial cloning.) A starfish can regenerate and eventually produce a whole new organism from a single severed appendage, while flatworms divide in two and regenerate to form two new flatworms. This formation of a separate organism is obviously much more complex than the simple splitting of single bacteria cells, but it is still a form of asexual reproduction.

Vegetative Propagation

Strawberries reproduce by forming growths called runners, which grow horizontally and generate new stalks. At some point, the runner decomposes, leaving a new plant that is a clone of the original. This is an example of vegetative propagation, a term for a number of processes by which crop plants are produced asexually. Vegetative propagation is used for such crops as potatoes, bananas, raspberries, pineapples, and some flowering plants. Its advantage to farmers is that the crops will be more uniform than those grown from seed. Furthermore, some plants are difficult to cultivate from seed, and the vegetative propagation of those plants makes it possible to grow crops that otherwise would not be available for commercial marketing.

In reproducing potatoes through vegetative propagation, farmers plant the so-called eyes to produce duplicates of the parent. With banana plants, the farmer separates the suckers that grow from the root of the plant and plants them. The farmer raising raspberry bushes bends the branches and covers them with soil, whereupon a process not unlike that of the runner growth of mosses takes place: the branches eventually grow into a separate plant, with their own root system, and ultimately can be detached from the parent plant.

Between Asexual and Sexual

The example of vegetative propagation suggests that there is not a sharp dividing line between sexual and asexual reproduction—that is, that many organisms can reproduce either way. This is true even of humans, who, in theory, could be cloned, though the technology to do so—let alone resolution of the ethical issues of the procedure—lies in the far distant future. (See Genetic Engineering for more on this subject.) Even humans, however, can use external fertilization, which is sexual reproduction without sexual intercourse (see Sexual Reproduction).

Plants go through a process known as alternation of generations, in which they alternate as sexual and asexual reproducers, or gametophytes and sporophytes, respectively. In the asexual stage, the sporophyte produces diploid reproductive cells called spores, which develop into gametophytes. These gametophytes produce haploid gametes, which then unite sexually to form a diploid zygote that grows into a sporophyte. In plain English, this means that the asexual "grand-parent" generates a sexually reproducing "child," which in turn produces a "grandchild" that is asexual, like its grandparent.

At one phase in the alternation of generation for mosses, for instance, male and female moss plants grow from spores. Male moss plants produce sperm cells, which, when the moss receives rainfall, are able to propagate because they have a medium (water) in which to move. They fertilize the female plants, producing zygotes. The zygote grows on top of the female moss plant, which helps to store moisture and thus provides a hospitable environment in which the zygote can develop. The zygote eventually produces haploid spores, which it releases into the air. These tiny spores, carried by the wind, float away from their point of origin until they come to rest, and soon the cycle begins once again.

Parthenogenesis

There are also organisms, including bees, ants, wasps, and other insects, that reproduce in a way that is neither fully sexual nor asexual. This is parthenogenesis, a type of reproduction in which a gamete develops without fertilization. In other words, a sex cell is reproduced without actual intercourse between male and female. The gamete is almost always female—a fact indicated in the name itself, which comes from parthenos, Greek for "maiden."

The Parthenon in Athens, like the city itself, is named after the goddess Athena (also called Minerva), who was known by the nickname Parthenos. She is said to have been born fully formed, having sprung from the head of her father, Zeus, dressed in armor and ready for battle. Thus, her own birth was a form of parthenogenesis, a word whose second half (a name well known from the Bible) means "beginning."

Pollen and Pollination

Pollen is a fine, powdery substance consisting of microscopic grains containing the male gametophyte of certain plants that reproduce sexually. These plants include angiosperms, a type of plant that produces flowers during sexual reproduction, and gymnosperms, which reproduce sexually through the use of seeds that are exposed and not hidden in an ovary, as with an angiosperm. Pollen is designed for long-distance dispersal from the parent plant, so that fertilization can occur. Pollination is the transfer of pollen from the male reproductive organs to the female reproductive organs of a plant, and it precedes fertilization. In other words, pollination is the equivalent of sexual intercourse for seed-bearing plants. Actually, cross-pollination, or the transfer of pollen from one plant to another, would perhaps be analogous to sexual intercourse in animals. Pollination occurs in seed-bearing plants, as opposed to the more primitive spore-producing plants, such as ferns and mosses. Gymnosperms, such as pines, firs, and spruces, produce male and female cones, whereas angiosperms produce flowers containing a male organ called the stamen and a female organ called the pistil. Both types of plants rely on insects and other creatures to aid in the pollen transfer.

Darwin's Moth

The German physician and botanist Rudolf Jakob Camerarius (1665-1721) was the first scientist to demonstrate that plants reproduce sexually, and he pioneered the study of pollination. One of the scientists influenced by his work was the English naturalist Charles Darwin (1809-1882), who discussed the subject in The Various Contrivances by which Orchids Are Fertilized by Insects (1862). Darwin wrote this book partly to support the ideas on evolution presented in his much more well known book Origin of Species (1859). In Various Contrivances, he suggested that orchids and their insect pollinators evolved by interacting with one another over many generations.

As an example, he discussed Angraecum sesquipedale, an orchid native to Madagascar. Darwin had not seen the plant in its native habitat, however; he had looked only at its dried leaves. The white flower of this orchid has a foot-long (30 cm) tubular spur with a small drop of nectar at its base, and from observing this, he hypothesized that the orchid had been pollinated by an insect with a foot-long tongue. This hypothesis, he wrote, "has been ridiculed by some entomologists," or scientists who study insects. After all, no such creature had been found in Madagascar. But then, around the turn of the nineteenth century—some two decades after Darwin's death—it was found. A Madagascan moth was discovered that had a foot-long tongue that uncoils to sip the nectar of A. sesquipedale as it cross-pollinated the flowers.

Plants and Their Pollinators

Angiosperms and gymnosperms are discussed in Ecosystems and Ecology, where each is compared in terms of its degree of adaptation to its environment. Angiosperms seem to be the hands-down winner: by enlisting the aid of insects and other pollinators, they manage to pollinate much more efficiently than gymnosperms, which have to produce vast quantities of pollen for each grain that reaches its target. Typically, pollination benefits the animal pollinator by supplying it with sweet nectar and, of course, benefits the plant by providing direct transfer of pollen from one plant to the pistil of another plant. For this reason, specific plant and animal species have developed a relationship of mutualism, a form of symbiosis in which each participant reaps benefits (see Symbiosis). In many cases, plant and pollinator have evolved together, and it is possible to determine which animal pollinates a certain flower species simply by studying the morphologic features (shapes), color, and odor of the flower.

For example, some flowers are pure red, or nearly pure red, and have very little odor. In most such situations, the pollinator is a bird species, since birds have excellent vision in the red region of the spectrum but a rather undeveloped sense of smell. It so happens that Europe, which has no pure red native flowers, also has no bird-pollinated native flower species. Not all bird-pollinated flowers are red, but they are all characterized by striking, and sometimes contrasting, colors that readily catch the eye. Examples of plants pollinated by birds include the cardinal flower, the red columbine, the hibiscus, the eucalyptus, and varieties of orchid, cactus, and pineapple.

Some flowering plants have a very strong odor but are very dark, or at least drab, in color. These flowers and plants—examples include the saguaro cactus, century plant, or cup-and-saucer vine—are often pollinated by bats, which have very poor vision, are typically active during the night, and have a very well developed sense of smell. The flowers of many plant species are marked with special pigments called flavonoids, which absorb ultraviolet light and appear to direct the pollinator toward the pollen and nectar. These pigments are invisible to humans and most animals, but bees' eyes have special ultraviolet photoreceptors that enable the bees to detect patterns and so pollinate these flowers.

Where to Learn More

"Asexual Reproduction Lab." Lester B. Pearson College of the Pacific (Web site). <http://www.pearson-college.uwc.ca/pearson/biology/asex/asex.htm>.

Canine Reproduction (Web site). <http://www.labbies.com/canine_reproduction_table_of_con.htm>.

CRES: The Center for Reproduction of Endangered Species/ San Diego Zoo (Web site). <http://www.sandiegozoo.com/conservation/cres_home.html>.

Elia, Irene. The Female Animal. New York: Henry Holt, 1988.

"Flowering Plant Reproduction." Estrella Mountain Community College (Web site). <http://gened.emc.maricopa.edu/bio/bio181/BIOBK/BioBookflowers.html>.

Kevles, Bettyann. Females of the Species: Sex and Survival in the Animal Kingdom. Cambridge, MA: Harvard University Press, 1986.

Kimball, Jim. "Asexual Reproduction ." Kimball's Biology Pages (Web site). <http://www.ultranet.com/~jkimball/BiologyPages/A/AsexualReproduction.html>.

Maxwell, Kenneth E. The Sex Imperative: An Evolutionary Tale of Sexual Survival. New York: Plenum, 1994.

The Pollination Home Page (Web site). <http://pollinator.com/>.

Reproduction (Web site). <http://www.factmonster.com/ce6/sci/A0841565.html>.

Topoff, Howard R. The Natural History Reader in Animal Behavior. New York: Columbia University Press, 1987.

Walters, Mark Jerome. The Dance of Life: Courtship in the Animal Kingdom. New York: Arbor House, 1988.

noun

1. Something closely resembling another: carbon copy, copy, duplicate, facsimile, image, likeness, reduplication, replica, replication, simulacrum. Archaic simulacre. Law counterpart. See same/different/compare.
2. The process by which an organism produces others of its kind: breeding, multiplication, procreation, proliferation, propagation, spawning. Obsolete increase. See reproduction/barrenness.

Definition: something duplicated; duplication
Antonyms: original

Reproduction is the process by which offspring are formed and genetic material is passed on from one generation to the next. In humans, reproduction is sexual.

Fertilization

Gametes are produced by the reproductive glands, or gonads. Female gonads (ovaries) produce ova and male gonads (testes) produce sperm. Both ovum and sperm are haploid, which means that they contain half the normal (diploid) amount of genetic material (DNA) of the adult. During coitus, about 100 million sperm are deposited in the vagina, but only a few hundred reach the site of fertilization in the fallopian tube. One sperm penetrates the ovum during a process that leads to the fusion of the sperm and ovum nuclei, which contain the DNA. This fusion restores the diploid chromosome number, so that offspring inherit about half of their genes from each parent.

The fertilized ovum, now called the zygote, undergoes repeated cell divisions as it moves toward the uterus and implants in the endometrium. Only 20 to 25 percent of fertilized ova result in successful pregnancies. The rest fail to divide, fail to implant, or miscarry. Many of these unsuccessful pregnancies are genetically abnormal.

Pregnancy

During the first trimester of pregnancy, the conceptus differentiates various specialized structures and organs, a process called embryogenesis. At the completion of this period, the embryo becomes a fetus. During the second and third trimesters, the fetus continues to grow and mature. By the ninth month, the fetus should be able to breathe on its own and maintain a normal body temperature. Survival rates are greater than 99 percent for babies born in most developed countries. Infant mortality is an important measure of public health and is influenced by many factors, including the proportion of births that occur prematurely or with birthweight that is too low. Other factors, such as the availability of services to ensure safe delivery and good health for mother and fetus, also influence infant mortality.

About 3 percent of infants have major congenital anomalies that are apparent in the first year of life. Such birth defects are the most frequent causes of infant mortality in many developed countries. Some congenital anomalies result from chromosomal abnormalities or mutations of single genes or gene pairs, but the cause of most birth defects is unknown. Many congenital anomalies appear to result from combinations of genetic and nongenetic factors that have not yet been identified.

Supplementation of the mother's diet with folic acid around the time of conception reduces the occurrence of neural tube defects and certain other birth defects. Reducing the occurrence of birth defects by folic acid dietary supplementation or food fortification is an important but largely unfulfilled public health opportunity.

Teratogenic exposures are thought to be responsible for about 10 percent of congenital anomalies. A variety of infections, medications, alcohol, and other agents can adversely affect embryonic or fetal development under certain exposure conditions. The embryo is most sensitive to damage from most teratogenic exposures between two and ten weeks after conception. Teratogenic exposures are an especially important cause of birth defects because they are potentially preventable.

Contraception

Contraception is the process or means used to prevent pregnancy. Contraceptive options include abstinence, spermicide, male condoms, female condoms, hormonal methods, diaphragm, intra-uterine devices (IUDs), and surgical sterilization. Different methods of birth control have different degrees of effectiveness against pregnancy and of protection against sexually transmitted diseases (STDs). Each method has specific advantages, risks, and limitations.

The most effective method of birth control is abstinence. This method is 100 percent effective against pregnancy and has a decreased risk of contracting STDs. For sexually active people, the effectiveness for pregnancy prevention by surgical sterilization or hormonal contraceptive methods, when properly used, is about 99 percent. IUDs and condoms with spermicide can provide protection against pregnancy that is almost as good, although inconsistent use is often a limiting factor in practice with methods such as condoms. Condoms can also provide protection against STDs.

The use of effective contraceptive methods has led to fewer unwanted pregnancies and possibly a decrease in the spread of STDs in industrialized countries. Declining infant mortality has produced a growing population and a greater need for family planning measures in most of the world, but the overall reproductive health of women has often received less attention. This is evidenced by high rates of maternal mortality and STDs. It is estimated that about 600,000 maternal deaths occur each year, with the overwhelming majority in developing countries. Close to 80 percent of these deaths are direct results of complications rising during pregnancy, delivery, or the post-partum period. The remaining 20 percent are due to preexisting maternal conditions that worsen during pregnancy, such as HIV/AIDS (human immunodeficiency virus/acquired immunodeficiency syndrome), malaria, heart disease, or hepatitis. Maternal mortality is highest in south and southeast Asia, sub-Saharan Africa, and Latin America.

One possible consequence of STDs is pelvic inflammatory disease (PID), a major cause of damage to female reproductive organs that can lead to death if untreated. Barrier contraceptive methods that decrease the risk of contracting STDs may also protect against PID. Oral contraceptive use is also associated with a decreased risk of PID, although the mechanism of this protection is unknown. IUDs are believed to increase the risk of PID, especially in women who are at an increased risk for STDs. PID currently affects about 1 million American women, most of whom are from lower socioeconomic classes.

Since no method of birth control except for complete abstinence is 100 percent effective, unwanted pregnancies do occur. In these cases, induced abortion may be used to terminate the pregnancy. Induced abortion has important ethical, psychological, and medical drawbacks when used as a substitute for contraception. Physical complications are frequent when abortions are done without proper sterile technique or by individuals who lack the necessary training and skills. Complications may include severe pain, infection, uterine perforation, hemorrhage, and death. Unsafe abortion is a major cause of death and illness for women of childbearing age. It is estimated that complications of unsafe abortions are responsible for 13 percent of maternal deaths. In some parts of the world, one-third or more of all maternal deaths are associated with unsafe abortions.

Infertility

Infertility is an inability to have children. In medical practice, infertility is diagnosed when a couple has been unable to conceive after one year of unprotected intercourse timed to coincide with ovulation. If the woman is over thirty-five years of age or has been unable to carry a pregnancy to term, this time is reduced to six months. Infertility affects 5.3 million Americans. Approximately 40 percent of infertility is due to female factors, 40 percent to male factors, and 20 percent to either combined or unknown factors. STDs and PID are two conditions that can lead to infertility in women. Therefore, educating the public about the risks of these infections is important in preventing infertility and improving women's health.

Conventional treatments for infertility depend on the cause and may include hormonal therapy and surgical procedures. In cases in which conventional methods fail, more advanced assisted reproductive technologies (ARTs) may be used. Current use of ARTs other than artificial insemination by donor is restricted because of limited availability, expense, and relatively low success rates.

Prenatal Diagnosis and Screening

A variety of prenatal diagnostic techniques are available for couples at increased risk of having a child with certain genetic or developmental abnormalities. These tests include amniocentesis and chorionic villous sampling (CVS). Such invasive techniques are associated with small risks of inducing pregnancy loss or fetal damage and require skilled operators and sophisticated ultrasonography equipment. Ultrasound examination and maternal serum screening tests, which are not associated with any known fetal risks, are used for routine pregnancy screening in some jurisdictions. These techniques can identify many, but not all, fetuses with Down syndrome or serious structural abnormalities such as spina bifida. Because very few fetal abnormalities can be treated effectively before delivery, prenatal screening or diagnosis may raise serious ethical and social issues related to the abortion of fetuses considered to be less than perfect.

Increased availability and public support of reproductive medical care and related educational and prevention initiatives in most developed countries have had an important beneficial effect on the health of women and young children. However, such services are not readily available in all parts of the world, and maternal and infant mortality as well as death and illness from STDs are far too frequent. Providing public health interventions to deal with these problems in an appropriate cultural, social, and religious context remains an urgent and often very challenging priority.

(SEE ALSO: Abortion Laws; Contraception; Maternal and Child Health; Population Growth; Population Policies; Pregnancy; Prenatal Care; Sexually Transmitted Diseases; Teratogens; Women's Health)

Bibliography

Carr, B. R., and Blackwell, R. E. (1998). Textbook of Reproductive Medicine. Stamford, CT: Appleton & Lange.

Enkin, M.; Keirse, M.; Neilson, J. et al. (2000). A Guide to Effective Care in Pregnancy and Childbirth, 3rd edition. New York: Oxford University Press.

Evans, A. T., and Niswander, K. R. (2000). Manual of Obstetrics, 6th edition. Philadelphia, PA: Lippincott Williams and Wilkins.

Frederiksen, M. C. (2000). Rypins' Intensive Reviews: Obstetrics and Gynecology. Philadelphia, PA: Lippincott Williams and Wilkins.

Friedman, J. M.; Dill, F. J.; Hayden, M. R.; and McGillivray, B. C. (1996). National Medical Series for Independent Study: Genetics. Philadelphia, PA: Lippincott Williams & Wilkins.

Hildt, E., and Graumann, S., eds. (1999). Genetics in Human Reproduction. Burlington, VT: Ashgate Publishing.

Killick, S. R. (2000). Contraception in Practice. London: Martin Dunitz Publishers.

Lambeau, N. C.; Morse, A. N.; and Wallach, E. E. (1999). The Johns Hopkins Manual of Obstetrics and Gynecology. Philadelphia, PA: Lippincott Williams and Wilkins.

World Health Organization (1999). AIDS Epidemic Updated: December 1999. Geneva: Author.

—— (1999). Reduction of Maternal Mobility. Geneva: Author.

— JAN M. FRIEDMAN; ROXANA MOSLEHI

For more information on reproduction, visit Britannica.com.

A woman's right to determine whether she will give birth was not legally recognized until the 1960s and 1970s, when U.S. Supreme Court decisions established that right. Until that time, women in the United States were denied access to birth control and to legal abortions by state criminal laws. Since the 1970s there has been ongoing controversy over legalized abortion, with the Supreme Court allowing states to impose restrictions on obtaining the procedure. In addition, medical science has developed techniques of artificial insemination and in vitro fertilization that enable pregnancy. These advances, in turn, have created opportunities for surrogate motherhood, opening up even more legal issues dealing with reproductive rights. Because of the cultural importance placed on motherhood and the intersection of religious beliefs and public policy, the debate over reproductive rights has been contentious.

Historical Background

In the nineteenth century, the average size of the U.S. family declined dramatically. A white woman in 1800 gave birth to an average of seven children. By the end of the century, the average was three-and-a-half children. In part the decline was caused by the dissemination of scientific information on birth control. Many of the nineteenth-century proponents of family planning were radical social reformers, who offended church and community leaders with their graphic descriptions of human reproduction.

Conservatives sought to curtail this information on birth control and abortion. The most prominent conservative watchdog was Anthony Comstock, a New York businessman who led a national reform effort against obscene materials. His work resulted in the federal Comstock Law of 1873, which criminalized the transmission and receipt of "obscene," "lewd," or "lascivious" publications through the U.S. mail. The law specified that materials designed, adapted, or intended "for preventing conception or producing abortion" were included in the list of banned items. Some states passed "little Comstock laws" that prohibited the use of contraceptives.

Until the second half of the nineteenth century, few states had criminal laws against abortion. Women in colonial times had used abortion to dispose of the offspring of rape or seduction. Abortion was not illegal under the common law as long as it was performed before "quickening," the period at about four or five months when the fetus begins to move in the womb.

State legislatures passed laws in the first half of the nineteenth century that adopted the quickening rule, and a few states allowed abortion after quickening to save the life of the mother. Abortions increased markedly in the 1850s and 1860s, especially among middle-class white women.

Religious leaders began to denounce abortion, but the American Medical Association (AMA) proved to be the most successful in ending legalized abortion. The AMA was formed in 1847, and the all-male professional group (women were not allowed to become doctors) made abortion law reform one of its top priorities. The AMA saw abortion reform as a way to increase its influence and to drive out unlicensed practitioners of abortion. By the 1880s medical and religious leaders had convinced all-male state legislatures (women were not allowed to vote) to impose criminal penalties on persons performing abortions and, in some states, on the women who had abortions. The laws were based on the states' police power to regulate public health and safety. This had some justification because abortion procedures of the time were dangerous, subjecting women to sterility and, in many cases, death. In response, women turned to birth control and to illegal abortions. The legal restrictions on birth control and abortion that were created in the late nineteenth century would not be removed until the 1960s and 1970s.

Birth Control

In the early twentieth century, a group of reformers sought to legally provide birth control information. The most prominent of these reformers was Margaret Sanger, who coined the term birth control. Sanger challenged state laws restricting birth control information, seeking to draw public support. Though the courts generally rebuffed her efforts, Sanger helped build a national movement. In 1921 she founded the American Birth Control League, which in 1942 became the Planned Parenthood Federation of America.

Renewed legal challenges to restrictive state laws began in the 1950s. By 1960 almost every state had legalized birth control. Nevertheless, laws remained on the books that prevented the distribution of birth control information and contraceptives. A specific target was the 1879 Connecticut little Comstock law that made the sale and possession of birth control devices a misdemeanor. The law also prohibited anyone from assisting, abetting, or counseling another in the use of birth control devices.

The Supreme Court reviewed the Connecticut law in Griswold v. State of Connecticut, 381 U.S. 479, 85 S. Ct. 1678, 14 L. Ed. 2d 510 (1965). Estelle Griswold was the director of Planned Parenthood in Connecticut. Just three days after Planned Parenthood opened a clinic in New Haven, Griswold was arrested. She was convicted and fined $100. The Connecticut courts upheld her conviction, rejecting the contention that the state law was unconstitutional.

The Supreme Court struck down the Connecticut birth control law on a vote of 7 to 2. In his majority opinion, Justice William O. Douglas announced that the law was unconstitutional because it violated an individual's right to privacy. Douglas asserted that "specific guarantees in the Bill of Rights have penumbras, formed by emanations from those guarantees that help give them life and substance. Various guarantees create zones of privacy." Thus, these "penumbras" (things on the fringe of a major region) and "emanations" added up to a general, independent right of privacy. In Douglas's view this general right was infringed by the state of Connecticut when it outlawed birth control. He said that the state cannot be permitted "to search the sacred precincts of marital bedrooms for telltale signs of the use of contraceptives."

The Griswold decision invalidated the Connecticut law only insofar as it invaded marital privacy, leaving open the question of whether states could prohibit the use of birth control devices by unmarried persons. In Eisenstadt v. Baird, 405 U.S. 438, 92 S. Ct. 1029, 31 L. Ed. 2d 349 (1972), the Court reviewed a Massachusetts law that prohibited unmarried persons from obtaining and using contraceptives. William Baird was arrested after giving a lecture on birth control to a college group and providing contraceptive foam to a female student. The Court struck down the law, establishing that the right of privacy is an individual right, not a right enjoyed only by married couples. Justice William J. Brennan, Jr., in his majority opinion, stated, "If the right of privacy means anything, it is the right of the individual, married or single, to be free from unwarranted governmental intrusion into matters so fundamentally affecting a person as the decision whether or not to beget a child."

With Griswold and Eisenstadt, state prohibition of birth control information and devices came to an end. These decisions also enabled schools to give more information to students concerning sex education. Some schools even dispense contraceptives.

Abortion

The establishment in Eisenstadt of an individual's right to privacy soon had dramatic implications for state laws that criminalized abortions. Until the 1960s abortion was illegal in every state, except to save the mother's life. The growth of the modern feminist movement in the 1960s led to calls for the legalization of abortion, and many state legislatures began to amend their laws to permit abortion when the pregnancy resulted from a rape or when the child was likely to suffer from a serious birth defect. However, these laws generally required a committee of doctors to approve the abortion.

State legislation was swept away with the Supreme Court's controversial decision in Roe v. Wade, 410 U.S. 113, 93 S. Ct. 705, 35 L. Ed. 2d 147 (1973). A class action lawsuit challenged the state of Texas's abortion law. Sarah Weddington, the attorney for "Jane Roe," argued that the Constitution allows a woman to control her own body, including the decision to terminate an unwanted pregnancy.

The Supreme Court, on a 7-2 vote, struck down the Texas law. Justice Harry A. Blackmun, in his majority opinion, relied on the prior right to privacy decisions to justify the Court's action. Blackmun concluded that the right to privacy "is broad enough to encompass a woman's decision whether or not to terminate her pregnancy." More importantly, he stated that the right of privacy is a fundamental right. This meant that the state of Texas had to meet the strict scrutiny test of constitutional review. Texas showed a compelling state interest because it had a strong interest in protecting maternal health that justified reasonable state regulation of abortions performed after the first trimester (three months) of pregnancy. However, Texas also sought to proscribe all abortions and claimed a compelling state interest in protecting unborn human life. Though the Court acknowledged that this was a legitimate interest, it held that it does not become compelling until that point in pregnancy when the fetus becomes "viable," capable of "meaningful life outside the mother's womb." Beyond the point of viability, the Court held that the state may prohibit abortion, except in cases where it is necessary to preserve the life or health of the mother.

The Court rejected the argument that a fetus is a "person" as that term is used in the Constitution and thus possesses a right to life. To find a fetus to be a person would make any abortion a homicide, which would prevent a state from allowing abortions in cases of rape or where the pregnancy endangers the life of the mother.

The Roe decision elicited a hostile reaction from opponents of abortion. The creation of a "pro-life" movement that sought to overturn Roe was immediate, becoming a new fixture in U.S. politics. Pro-life forces sought a constitutional amendment to undo the decision, but it fell one vote short in the U.S. Senate in 1983. Over time, as the composition of the Supreme Court has changed, the Court has modified its views, without overturning Roe.

In the 1970s a majority of the Court resisted efforts by some states to put restrictions on a woman's right to have an abortion. In Planned Parenthood of Central Missouri v. Danforth, 428 U.S. 52, 96 S. Ct. 2831, 49 L. Ed. 2d 788 (1976), the Court struck down a Missouri law that required minors to obtain the consent of their husbands or parents before obtaining an abortion. In 1979, in Bellotti v. Baird, 443 U.S. 622, 99 S. Ct. 3035, 61 L. Ed. 2d 797, the Court invalidated a similar Massachusetts law. Both opinions emphasized the personal nature of abortion decisions and the fact that the state cannot give someone else a veto over the exercise of one's constitutional rights.

In Akron v. Akron Center for Reproductive Health, 462 U.S. 416, 103 S. Ct. 2481, 76 L. Ed. 2d 687 (1983), the Court struck down a city ordinance that required that all abortions be performed in hospitals; a twenty-four-hour waiting period pass before an abortion could be performed; certain specified statements be made by a doctor to a woman seeking an abortion to ensure that she made a truly informed decision; and all fetal remains be disposed in a humane and sanitary manner. The Court held that these requirements imposed significant burdens on a woman's exercise of her constitutional right without substantially furthering the state's legitimate interests.

Opponents of abortion were successful, however, in preventing the payment of public funds for abortions not deemed medically necessary. In Maher v. Roe, 432 U.S. 464, 97 S. Ct. 2376, 53 L. Ed. 2d 484 (1977), the Court upheld a Connecticut state regulation that denied Medicaid benefits to indigent women seeking to have abortions, unless their physicians certified that their abortions were medically necessary. The Court found the law permissible because poor women were not a "suspect class" entitled to strict scrutiny review and because the regulation did not unduly burden the exercise of fundamental rights. In 1980 the Court upheld a provision of federal law, commonly known as the Hyde amendment, forbidding federal funds to support nontherapeutic abortions (Harris v. McRae, 448 U.S. 297, 100 S. Ct. 2671, 65 L. Ed. 2d 784).

During the 1980s and 1990s, the conservative majority on the Court showed more deference to state regulation of abortions. In Webster v. Reproductive Health Services, 492 U.S. 490, 109 S. Ct. 3040, 106 L. Ed. 2d 410 (1989), the Court upheld a Missouri law restricting abortions that contained the statement, "the life of each human being begins at conception." On a 5-4 vote, the Court upheld a law that forbids state employees from performing, assisting in, or counseling women to have abortions. It also prohibited the use of any state facilities for these purposes and required all doctors who would perform abortions to conduct viability tests on fetuses at or beyond twenty weeks' gestation.

In 1991 the Court upheld federal regulations imposed by the Reagan administration that barred birth control clinics that received federal funds from providing information about abortion services to their clients (Rust v. Sullivan, 500 U.S. 173, 111 S. Ct. 1759, 114 L. Ed. 2d 233). The Supreme Court found the regulation to be a legitimate condition imposed on the receipt of federal financial assistance.

The Court appeared to be ready to overturn the Roe precedent, but it surprised observers when it upheld Roe in Planned Parenthood v. Casey, 505 U.S. 833, 112 S. Ct. 2791, 120 L. Ed. 2d 674 (1992). The Pennsylvania law restricting abortions required spousal notification, parental consent in cases of minors, and a twenty-four-hour waiting period before the abortion could be performed. Similar requirements had been struck down by the Court before.

On a 5-4 vote, the Court reaffirmed the essential holding of Roe that the constitutional right of privacy is broad enough to include a woman's decision to terminate her pregnancy. Though there was no majority opinion, the controlling opinion by Justice Anthony M. Kennedy, joined by Justices Sandra Day O'Connor and David H. Souter, defended the reasoning of Roe and the line of cases that followed it. However, the joint opinion abandoned the trimester framework and declared a new "undue burden" test for judging regulations of abortion. Using this test, the joint opinion upheld the parental consent, waiting period, and record-keeping and reporting provisions, but invalidated the spousal notification requirement.

Pregnancy and Medical Developments

Artificial insemination, in vitro fertilization, and embryo transplants have created new opportunities for conceiving children. With artificial insemination, sperm from a donor is introduced into the vagina or cervix of a woman by any method other than sexual intercourse. Originally this technique was used when a husband was sterile or impotent, but it is now available to women regardless of whether they are married. For example, a lesbian couple could use artificial insemination to start a biological family.

The technique of in vitro fertilization gained international attention with the birth of Louise Brown, the first child conceived by in vitro fertilization, in England in 1978. This technique involves the fertilization of the egg outside the womb. The embryo is then transferred to a woman's uterus.

Because sperm and eggs can be frozen and stored indefinitely, there are occasional legal disputes over the rights to these genetic materials when a husband and wife divorce.

These techniques have led to surrogate motherhood. In these cases a woman agrees to be either artificially inseminated by a sperm-donor father or have a fertilized ovum inserted into her uterus. After giving birth, the surrogate mother legally surrenders the infant to the person or couple who will adopt and rear the child. The idea of surrogate motherhood is attractive to some couples because a child born of a surrogate mother will share half or all the genetic material of the parents who will raise the child.

Many surrogate mothers are close friends or relatives of the childless couple. However, the practice of commercial surrogate arrangements has increased greatly since the late 1980s. Many major cities have surrogate agencies, which are often run by doctors and lawyers, that maintain lists of potential surrogate mothers and help match a woman with a couple wanting to have a baby. Commercial surrogate agencies typically charge a fee of $10,000 or more to make the arrangements, which is in addition to the surrogate mother's expenses and fees, which may range from $10,000 to $100,000.

Commercial surrogate arrangements are not legal in all states, and there is little case law on the subject. Some states declare surrogacy contracts null, void, and unenforceable because they are against public policy. Opponents of commercial surrogacy believe that such arrangements exploit the surrogate mother and turn children into a commodity. They also are concerned that if a child is born with a disability, the adoptive parents may decline to take the child. Finally, there is the issue of the surrogate mother who does not wish to surrender the child after birth.

The so-called Baby M case illustrates the legal complications that accompany an attempt by a surrogate mother to assert the right to keep the child. In 1987 Mary Beth Whitehead agreed to be the surrogate mother for the sperm-donor father, William Stern. Whitehead signed a contract agreeing to turn over the child to Stern and his wife, in return for a payment of $10,000. When Whitehead refused to turn over the baby, whom she called Melissa, Stern went to court seeking custody of the girl to whom he referred as Sara. The New Jersey Supreme Court held that the surrogate contract was against public policy and that the right of procreation did not entitle Stern and his wife to custody of the child (In the Matter of Baby M, 109 N.J. 396, 537 A.2d 1227 [1988]). Nevertheless, based on the best interests of the child, the court awarded custody to the Sterns and granted Whitehead visitation rights.

Reproductive Hazards in the Workplace

Legal disputes have arisen when employers have barred pregnant women and women of childbearing age from jobs that pose potential hazards to the fetus. The Supreme Court, in United Auto Workers v. Johnson Controls, 499 U.S. 187, 111 S. Ct. 1196, 113 L. Ed. 2d 158 (1991), ruled that a female employee cannot be excluded from jobs that expose her to health risks that may harm her fetus. The Court found that the exclusion of the women violated title VII of the Civil Rights Act of 1964 (42 U.S.C.A. § 2000e et seq.) because the company policy only applied to fertile women, not fertile men. Justice Blackmun, in his majority opinion, noted that the policy singled out women on the basis of gender and childbearing capacity rather than on the basis of fertility alone. Concerns about the health of a child born to a worker at the plant were to be left "to the parents who conceive, bear, support, and raise them [the children] rather than to the employers who hire those parents."

See: Adoption; Fetal Rights; Fetal Tissue Research; Genetic Engineering; Griswold v. Connecticut; Husband and Wife; Penumbra; Roe v. Wade; Sex Discrimination; Women's Rights.

1. the process by which a living entity or organism produces a new individual of the same kind. It may be asexual or sexual.
2. the creation of a similar object or situation; duplication; replication.
In sexual reproduction the gonads, or sex glands—the ovaries in the female and the testes in the male—produce the germ cells that unite and grow into a new individual. Reproduction begins when the germ cells unite, the process called fertilization.

• asexual r. — reproduction without the fusion of germ cells; usually by budding or fission.
• cytogenic r. — production of a new individual from a single germ cell or zygote.
• sexual r. — reproduction by the fusion of a female germ cell with a male sexual cell or by the development of an unfertilized egg.
• somatic r. — production of a new individual from a multicellular fragment by fission or budding.

Dansk (Danish)
n. - reproduktion, gengivelse

Nederlands (Dutch)
voortplanting, reproductie, kopie

Français (French)
n. - reproduction

Deutsch (German)
n. - Reproduktion, Wiedergabe, Fortpflanzung

Ελληνική (Greek)
n. - αναπαραγωγή, αντίγραφο καλλιτεχνήματος, ρεπροντιξιόν, αναπαράσταση, αντίγραφο

Italiano (Italian)
riproduzione

Português (Portuguese)
n. - reprodução (f)

Русский (Russian)
репродукция, воспроизведение, размножение

Español (Spanish)
n. - reproducción, copia, procreación, multiplicación

Svenska (Swedish)
n. - reproducering, avbildning, förnyad produktion, fortplantning

中文（简体）(Chinese (Simplified))
再现, 生殖, 复制, 复制品

中文（繁體）(Chinese (Traditional))
n. - 再現, 生殖, 複製, 複製品

한국어 (Korean)
n. - 배생 , 복제, 생식

日本語 (Japanese)
n. - 再生, 再現, 再演, 複写, 模造品, 繁殖, 再生産, 複製品

العربيه (Arabic)
‏(الاسم) اعادة انتاج‏

עברית (Hebrew)
n. - ‮שעתוק, רפרודוקציה, שחזור, הולדה, העתקה, רבייה, איכות של הקלטת קול, עצם המחקה סגנון מסוים או תקופה מסוימת‬

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