Human Fertility
Men and women have hormonal cycles which determine both when a woman can achieve pregnancy and when a man is most virile. The female cycle is approximately twenty-eight days long, but the male cycle is variable. Men can ejaculate and produce sperm at any time of the month, but their sperm quality dips occasionally, which scientists guess is in relation to their internal cycle.
Furthermore, age also plays an equally significant role for both men and women.
Read more about this topic: Fertility
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