Reproductive experiences for women in today's affluent Western nations
differ from those of women in hunting and gathering societies, who co
ntinue the ancestral human pattern. These differences parallel commonl
y accepted reproductive risk factors for cancers or the the breast, en
dometrium and ovary. Nutritional practices, exercise requirements, and
body composition are nonreproductive influences that have been propos
ed as additional factors affecting the incidence of women's cancers. I
n each case, these would further increase risk for women in industrial
ized countries relative to forager women. Lifestyles and reproductive
patterns new from an evolutionary perspective may promote women's canc
ers. Calculations based on a theoretical model suggest that, to age 60
, modern Western women have a breast cancer risk as much as 100 times
that of preagricultural women.