Is there any truth to men wanting to have sex more often than women do?

Actually, there is a biological reason men seem to be in the mood more often then women, and why women suffer more from the proverbial headache, says Judy Seifer, Ph.D., R.N., a professor of sexual health at the Institute for the Advanced Study of Human Sexuality in San Francisco. "In both men and women, sexual drive is controlled by the testosterone manufactured in our bodies," explains Seifer. Since postpubescent men have constant levels of androgens (a hormone that includes testosterone) running through their bodies, they maintain a pretty constant interest in sex. Androgen levels only begin to slowly decrease when a man is in his 60s, says Seifer. Postpubescent women, on the other hand, are a bit more complicated. As a result of the 28-day menstrual cycle, women's moods and sexual desires correlate directly with their shifting levels of hormones progesterone and estrogen. "Unlike testosterone, these hormones can lower a woman's sex drive by promoting bloating, tenderness, and irritability," says Seifer. When is a woman most likely to feel in the mood? "The first few days after she gets her period," says Seifer. "Since estrogen and progesterone levels are extremely low at this point in the cycle, the testosterone in a woman's body is able to shine through and do its job."