A 9 year old in Africa was the youngest recorded conception at this point. Girls as young as 6 have been recorded to start their menstrual cycle, so it could theoritically be as young as that. 5 years old peruvian girl, see http://www.snopes.com/pregnant/medina.asp
Human babies are only born when the sperm of a human male fertilizes the egg of a human female and conception occurs. Human babies are only born to humans.
The first stage is conception, in which is the making and having of the female or male child.
The global gender probability, at birth, is approx 0.517 for male and 0.483 for female. This is not the same as the gender ratio at conception because of gender-specific abortion.
At conception.
At conception.
The placenta will be attached to the uterus, but it is not part of it. The uterus is a muscle and is part of basic female human anatomy. The placenta is an organ which is formed after conception.
The menstrual cycle in human beings is the reproductive cycle. A female will ovulate and uterine lining will plump up ready for an embryo to implant, if conception doesn't occur the uterine lining sheds (menstruation).
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Conception and death.
No, animal semen cannot get a human female pregnant. Only human semen can impregnate a human female.
Zygote!
Roughly 10 days after conception