What is the definition of conception?

Answer 1

Conception is the onset of a pregnancy in the reproductive process.

Exactly when it happens in that process has been debated, but the biological definition of conception is usually accepted as the onset of pregnancy that begins when the fertilized cell (blastocyst) implants itself in the lining of the womb of the mother (called the endometrium).

Once implanted and sustainable on the lining of the uterus/womb, development of the offspring can begin and conception is said to have occurred. Some people prefer to define it as beginning once there is fertilization of the ovum/egg by the sperm.

In the process of reproduction, first the male sperm are released during coitus (in natural fertilization), and begin traveling toward an egg in the female's body. When a sperm detects the ovum, usually in the Fallopian tube or sometimes already in the uterus, it penetrates the zona (outer layer) of the ovum and fertilization occurs. This initiates the formation of a zygocyte. The zygocyte is also known as a zygote, the two-celled result of fertilization in humans and most other mammals, and is also known as a diploid cell.

The zygote is what eventually becomes an embryo once it starts to develop and grow in the womb. It is called an embryo until the eighth week of implantation in the uterine wall. After the eighth week, it is then known as a fetus. A fetus will continue to develop during the months of pregnancy and, if all goes well, it will then be delivered once fully developed (it varies but typically around 9 months). Once delivered, the fetus is called a newborn or newborn infant for the first 28 days after birth (the end of the perinatal period which begins just before birth until 28 days after delivery). Following that it is called an infant.