To make matters worse, the erotic stories in sex publications such as Penthouse imply that every woman self-lubricates like Niagara Falls at the wink of an alluring eye: "Just being near Bill made my panties wet." Not only is this way off the mark, but it has led to a destructive corollary, the notion that if a woman does not produce much natural lubrication, she is neither turned on by her lover nor committed to the relationship.

Instant gushing lubrication may happen to some women. But it's much more common for a woman to feel committed to her relationship and erotically aroused by her lover, and still not self-lubricate much, if at all.

Some women naturally produce less vaginal lubrication than others. Just as height varies, so does propensity to self-lubricate. There is nothing wrong with women at any point along the self-lubrication spectrum, says Louanne Cole Weston, a sex therapist in Fair Oaks, Calif. It's just who they are. Unfortunately, women who do not produce much lubrication often feel abnormal, even though they are not. (Meanwhile, women who become "too" self-lubricated may also feel abnormal, and suffer embarrassment about soaking the sheets.)

Estrogen is a major factor in vaginal self-lubrication, according to Cathy Winks and Anne Semans, coauthors of "The Good Vibrations Guide to Sex." The more of the sex hormone in a woman's bloodstream, the more she self-lubricates. Estrogen production begins to decline during a woman's 40s as she approaches menopause. Some women notice decreased self-lubrication as early as their late 30s. After menopause, vaginal dryness becomes a real problem for many women. Hormone replacement therapy may help, but even with supplemental estrogen, some postmenopausal women experience persistent dryness.

In reproductive-age women, estrogen levels fluctuate during the menstrual cycle, resulting in different amounts of lubrication throughout the month, Winks and Semans note. Its viscosity may also vary. The same goes for pregnancy, childbirth and nursing.

Emotional stress is also a factor in self-lubrication. Everything from job hassles to relationship tensions can impair sexual response in both men and women. In men, the result can be erection impairment; in women, a reduction in self-lubrication. Drug use also affects self-lubrication, according to Theresa Crenshaw, M.D., and James Goldberg, coauthors of "Sexual Pharmacology." Many over-the-counter and prescription medications decrease vaginal lubrication, among them alcohol, cigarettes and anything that dries the mouth (antihistamines, cold formulas, marijuana) and certain antidepressants (Elavil, Anafranil, Tofranil and Sinequan, among others). Some women report that birth control pills reduce lubrication.

Private Life Romance, relationships, and the personal side of Table Talk