`VENUS-MARS' GAP ALSO IN SEX AFTER ABSENCE?

Byline: Malcolm Ritter Associated Press 

Absence really could make a man's heart grow fonder, but it doesn't appear to make his sweetheart any more interested in sex with him, a study suggests.

In a survey of people on and around college campuses, researchers found that the more time spent apart after sex, the more eager men were to copulate with their lovers again.

Women were generally unaffected by separation, according to the study led by Todd K. Shackelford, an assistant professor of psychology at Florida Atlantic University.

It didn't matter how much time had lapsed since the couple last had sex.

Don't take it personally, guys. The researchers propose in a paper presented Friday at the annual meeting of the American Psychological Association that you're unwittingly responding to an urge from way back in human evolution.

Basically, the researchers suggest, the urge that drives a man to want sex after separation is the thought that another man might have gotten there first and beat out his sperm in the race to fertilize his partner's egg. After all, in the view of evolutionary biology, passing on genes to the next generation is what sex is all about.

The notion of ``sperm competition'' within a female has been well-studied in nonhumans, but whether it significantly shapes sexual behavior in people is open to debate.

Shackelford acknowledged the measured effect of time apart on men's attitudes about sex is small. Many other factors could affect how interested a man is in sex on a given day. The results of the study are preliminary and, since they come from a one-time survey, can suggest only that time apart affected men's attitudes.

The researchers gave anonymous one-time questionnaires to 388 women and 304 men who said they were in committed sexual relationships. The participants, in their mid-20s on average, were recruited at universities and nearby public areas in Texas, Florida and Germany.

Participants rated their current interest in their partner on a 10-point scale. Results suggest that for every 100 hours of time apart since the last time they had sex with their partner, men's interest in doing it again rose an average of about one point, and their rating of their partner's attractiveness rose about a half-point.

Similarly, the less time men had spent with their partners since last intercourse, the higher they rated the partner's sexual interest in themselves and her attractiveness to other men. It didn't matter how much total time had elapsed since the last copulation.

Women, in contrast, appeared unaffected by the amount of time spent apart.

The new work proposes a psychological underpinning for earlier controversial research. The prior work found evidence that the more time a man spent apart from his sexual partner since they last had sex, the more sperm he ejaculates at the next copulation.

But Timothy Perper, an independent sex researcher in Philadelphia and author of ``Sex Signals: The Biology of Love,'' said he doubted that Shackelford had really detected a psychological signal of sperm competition.

For one thing, Perper said, the researchers didn't directly test whether the male-female differences were big enough to be considered real rather than just a fluke. If there's no real difference, there's no evidence for sperm competition, he said.

He noted that the results didn't support two other tested predictions from sperm competition theory. Time apart was not related to how much a man figured his partner was sexually interested in other men, nor how distressed he was if his partner refused to have sex.

Shackelford said the questionnaire may have just done a poor job of asking about those things.