(FORTUNE Magazine) – When a patient goes to see the Berman sisters, they may ask her to stimulate herself with a vibrator or watch erotic films with a probe attached to her labia. And when it's time to write a prescription, they might send her home with an EROS Therapy device. This small suction pump, which looks a lot like a computer mouse and runs on batteries, has a plastic cup that fits over the clitoris and stimulates blood flow to the area.

What's going on here? Something important and new. Urologist Jennifer Berman and psychotherapist Laura Berman are co-directors of the Female Sexual Medicine Center at UCLA and among the nation's leading practitioners in the burgeoning field of female sexual dysfunction (FSD). If you've never heard of FSD, that's not surprising; the medical establishment did not officially define it until 1998. Yet FSD--which includes low libido, difficulty reaching orgasm, insufficient lubrication or genital sensation, and pain during intercourse--is depressingly common. According to a 1999 article in the Journal of the American Medical Association, 43% of U.S. women experience some form of sexual dysfunction sometimes.

How best to treat it? Men's sexual dysfunction typically involves being unable to have or sustain an erection, so Viagra is just what the doctor ordered. But women's sexuality is much more complex, and FSD tends to have a stew of emotional and physiological causes. The EROS is the only treatment approved by the FDA specifically for FSD. Yet some drugs being prescribed appear to help some women some of the time, and the labs are working overtime on new ones.

Hormones, for example, have been known to produce the desired desire. A woman's testosterone level drops significantly between her 20s and 40s and tumbles further at menopause. Because testosterone may be linked to libido, one theory is that restoring depleted levels could revive the sex drive. Prescription testosterone creams appear to help some women; better options are likely on the way, such as a testosterone patch worn on the abdomen that Procter & Gamble's pharmaceuticals division is testing. Preliminary results show improved sexual function when used by women after hysterectomies or removal of ovaries. (P&G will soon start Phase III clinical trials; if you're interested in participating, call 877-290-2379.) Estratest, a menopause drug that combines estrogens and androgens, improves genital lubrication; Solvay Pharmaceuticals is testing its efficacy on low libido.

Drugs based on a chemical called apomorphine could help treat sexual dysfunction in both sexes. They stimulate receptors in the midbrain to send signals down the spinal cord to increase blood flow to the genitalia and boost libido. For women, that could mean enhanced sensation and lubrication. Uprima, a product whose active ingredient is apomorphine, has been approved in Europe for use against erectile dysfunction; Nastech, a drug company in Hauppage, N.Y., is testing versions for women and men. Administered through a nose spray, Nastech's medication reaches maximum concentration in 15 minutes. It will be several years before it can be submitted for FDA approval.

What about good old Viagra? Sildenafil, its active ingredient, works on men by blocking an enzyme that prevents erections from happening, freeing up blood flow to the penis. Theorizing that Viagra can increase blood flow to women's genitals too, some doctors are prescribing it for women and reporting that it works for some. Pfizer, Viagra's maker, is working on a female version. So far, though, concedes spokesman Geoff Cook, "we're not able to show efficacy over a placebo."

Remember that for most women the solutions to FSD are both physical and emotional. So while you're waiting for a magic pill, patch, or potion, you might work on that other crucial sexual aid: a good and loving relationship.

--CAIT MURPHY