The female orgasm is the Rodney Dangerfield of the scientific world: It can't get no respect.
Some evolutionists argue that it is functionless, a biological bimbo, that the clitoris is an underdeveloped penis caused by an oddity of embryonic development.
Evolutionary psychologists say it influences bonding and mate selection, sort of the orgasm-makes-the-heart-grow-fonder theory.
Darwinian theorists claim that female orgasm is a device to make women lie down and sleep after sex, minimizing the loss of those marathon-swimming sperm cells.
But soon-to-be-published research suggests that a woman's sexual climax has a more active reproductive purpose. The uterine contractions during orgasm may greatly increase a woman's chance of becoming pregnant by propelling sperm from the uterus into the Fallopian tubes, where eggs are fertilized.
"It used to be that doctors and scientists didn't think a female orgasm was important to conception," says Dr. Laura Quinton, a research fellow at Hammersmith Hospital in London. "But that may be changing with proper scientific research on the subject."
Research suggests that with the powers of the female orgasm behind them, sperm can travel more quickly to the Fallopian tubes. While no one knows for sure how much faster female orgasm speeds sperm to their destination, researchers believe its effect is substantial. Still other studies suggest the female orgasm--when timed properly in relation to a man's ejaculation--pulls in and retains greater numbers of sperm.
Women, of course, do conceive without orgasm, but the virtuoso vacuum power of female climax may be the ideal helpmate for a man with a low sperm count.
Quinton tracked 300 women trying to conceive, finding that those whose difficulty could not be explained by such physical problems as blocked Fallopian tubes were less likely to have orgasms than the others. (All men were screened for infertility.)
All couples in the study reported having equal amounts of sex, but the women who conceived and the women with tubal infertility said they had regular orgasms. Women with unexplained infertility reported having orgasms infrequently, said sex was less satisfying and described communication about sex with their partner as difficult.
Quinton said couples whose infertility has nonphysical causes experience stress about its mystical nature and find it affects their sex lives. She advises better communication and more information about how the woman can achieve orgasm--not only to increase her pleasure but also to enhance the chances of conception.
British biologists Robin Baker and Mark Bellis have also studied the role of orgasm in conception and have dubbed the phenomenon the "upsuck effect."
In their study, the biologists asked women to keep track of the timing of their orgasms and to collect ejaculate flowing back from the vagina after copulation. Sperm was gathered from more than 300 instances of sexual intercourse.
Baker and Bellis found that if a woman climaxes sometime between a minute before or 45 minutes after her lover ejaculates, she retains markedly more sperm than she does following non-orgasmic sex. If she climaxes more than a minute before or more than 45 minutes after her mate ejaculates, little sperm is retained.
The biologists speculated that by timing her orgasm relative to her mate's, a woman can influence her reproductive fate--by subconsciously deciding whether to turbocharge the sperm cells of this particular partner. (The upsuck effect is also at work in some animals. Scientists found that a mare's uterus could pull in an impressive 27 ounces of fluid in five seconds.)
But in the battle to procreate, the male sperm supply is anything but a wimpy bystander. The biologists also found that the longer a woman is away from her partner, the more sperm her mate ejaculates upon copulatory reunion. The biologists suggest that the increased amount of ejaculate may be generated automatically to compensate for the risk that a mate was inseminated by an interloper.
Certainly, most women blinded by orgasmic pleasure waves are not thinking about babies. And most women are probably not having mental flashes of selecting "superior sperm" during sexual climax. Still, it's comforting to know that women's orgasmic machinery is shedding the brainless bimbo image and is finally getting some respect.