Female Supremacy Articles - Page 6

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Women's life span depends on the balance of two forces, according to Thomas Perls, a geriatrician at Harvard Medical School. One is the evolutionary drive to pass on her genes, the other is the need to stay healthy enough to rear as many children as possible. "Menopause draws the line between the two," Perls says. It protects older women from the risks of bearing children late in life, and lets them live long enough to take care of their children and grandchildren.

As for men, Perls believes "their purpose is simply to carry genes that ensure longevity and pass them on to their daughters. Thus, female longevity becomes the force that determines the natural life span of both men and women."

"Most animals do not undergo menopause," adds Ruth Fretts, an obstetrician-gynecologist at Harvard-affiliated Beth Israel Deaconess Medical Center in Boston. "It seems that menopause evolved in part as a response to the amount of time that the young remain dependent on adults to ensure their survival."

Pilot whales, for example, suckle their young until age 14, and they, along with humans, are two of the few species that menstruate.

Human females eventually become so frail that bearing children involves a high risk of death. Earlier in evolution, that was as young as 35 to 40 years old. "Anyone who developed a genetic alteration that caused infertility, i.e., menopause, obtained a survival advantage over females who continued to be fertile and died bearing children," Perls says.