A Dose of Desire

"I could get to seventh heaven years ago, and now I can get to fifth," she says. "That's far better than purgatory."

The Flops

On one point everyone agrees: The search for pink Viagra is proving trickier than anticipated. So far it's been one flameout after another.

There was PT-141, by Palatin Technologies of New Jersey, a drug inhaled via nasal spray and found, in preliminary tests, to produce friskiness in both men and women, leading to buzz in 2005 that people would soon be able to snort themselves into the mood. "The first real, honest-to-God, horny-making, body-shaking, equal-opportunity aphrodisiac," panted New York magazine that year.

Nuh-uh. In August, the FDA stopped clinical testing, citing concerns about a side effect high blood pressure.

There was Intrinsa, a patch made by Procter & Gamble that transmitted testosterone into the bloodstream through the skin. (Testosterone, associated with sex drive, is produced naturally in women, though in far lower quantities than in men.) Also dinged by the FDA.

And of course, long before modern medicine, there were zany experiments with ointments, insects and ground-up rhinoceros horns. The search for a female aphrodisiac is apparently as old as wooing.

What's taking so long?

With men, all a medication needs to produce is arousal, a.k.a. an erection. A guy will conjure lust on his own. A woman, on the other hand, can get aroused -- or have the physical signs of arousal -- and remain uninterested in sex. That's why Viagra doesn't work for the ladies, even though it produces roughly the same physical effect on them as on men. (In simplest terms, the drug rushes blood to the nether regions and creates the symptoms known as "hot and bothered.")

Arousal for women does not always lead to desire: Even Pfizer had a hard time grasping that concept. The company tested 3,000 women over the course of eight years before finally abandoning hope, in 2004, that Viagra itself could be the female Viagra.

"What we know is that very little of what's going on with women and sex is below the waist," says Anita Clayton, a professor at the University of Virginia's Center for Psychiatric Clinical Research and co-author of "Satisfaction: Women, Sex and the Quest for Intimacy." "Almost all of it is above the neck."

Which gets you to another complexity: If lust is "above the neck" for women, how exactly do you measure it? To win the pink Viagra sweepstakes, the FDA wants data demonstrating an increase in the number of a woman's "sexually satisfying events." But that's hard to define and fantastically varied, and it doesn't necessarily translate as "orgasm."

So pink Viagra must clear a higher hurdle than Viagra ever did -- it has to spark desire that also leads to satisfying events. To Clayton, it seems as if the government has set a standard that is unreasonably high -- perhaps because the government doesn't actually want to see a desire drug marketed to women, for vaguely puritanical reasons.