Tuesday 11 September 2018

human biology - When are a female's eggs created?


Since a human woman is born with a set number of eggs, and meiosis is the process by which sex cells are produced, would meiosis in a woman happen before she is born or soon after she was born?


If meiosis creates sex cells and women are born with a set number of sex cells, when in the development of a woman are her sex cells created?



Answer



Oocytes, or immature female eggs, develop in the fetus's ovaries during pregnancy. This graph (U. New South Wales) shows the oocyte population over time in a human female:


graph of oocytes in human body



Although the x-scale is kind of confusing (months when negative, years when positive), you can see that the fetus has all the oocytes it will ever have at the peak 18-22 weeks after conception. Since age 0 is birth, meiosis in a woman happens long before she is born.


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