Several aspects of female reproductive biology appear to be different between great apes and humans. Menopause is a natural state in human females that has not been observed in long-lived captive female chimpanzees (Graham 1979). Human females are also unusual in typically having obviously visible breasts in the absence of pregnancy or lactation, and in having a high frequency of breast diseases (fibrocystic disease and cancer, in particular). Also, the absence of external signs of ovulation in human females may result in fertilization taking place at suboptimal times with regard to the condition of the ovum. Thus, the question arises whether fertilization of deteriorating eggs may explain at least partly the high rate of early fetal wastage in humans that is typically associated with gross chromosomal and other genetic abnormalities. Regarding menstruation, anecdotal evidence suggests that the volume of blood lost per normal cycle might be significantly larger in humans, and that menometrorrhagia (excessive and frequent bleeding seen particularly in perimenopausal humans) is not common in great apes. These issues obviously have significant effects on the health and lifestyle of human females. Because the other general features of human and chimpanzee female reproductive biology (e.g., the overall ovarian cycle) are quite similar, comparative genomics could help unveil the basis for the unusual human features, each of which has some biomedical implications.