الفهرس 
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Abstract
Fertility is the natural capability to produce offspring. Human fertility depends on factors of nutrition, sexual behavior, culture, instinct, endocrinology, timing, economics, way of life, and emotions. 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 can deviate greatly from this ”norm”. The male cycle is also 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 The average age of menarche in the United States is about 12.5 years (Anderson, et al, 2003). In postmenarchal girls, about 80% of the cycles are an ovulatory in the first year after menarche, 50% in the third and 10% in the sixth year (Apter, 1980). Women’s fertility peaks in the early 20s, and drops considerably after age 35. Menopause typically occurs during a women’s midlife (usually between ages 45 and 55. During menopause, hormonal production by the ovaries is reduced, eventually causing a permanent cessation of the primary function of the ovaries, particularly the creation of the uterine lining (period). This is considered the end of the fertile phase of a woman’s life (Leridon,2004).