Rople tend to think that a person's sexual orientation is a sort of black -or-white affair: Either you're heterosexual or you're homosexual, and that's that.
But the matter is just not that simple. Human sexual desire is both enormously mysterious and bewilderingly diverse- it's more like a vast spectrum of color than a simple division between black and white. A huge number of people are exclusively heterosexual during their entire adult lives; a far smaller number are exclusively homosexual. But there's also a vast number of people who fall somewhere in between - people whose sexual desires are aroused, either often or occasionally, in fantasy or in fact, by both men and women.

Drawing the "Bi" Line
People in this group are known as bisexuals-although even sex researchers are not exactly sure how to define this term. Are you a bisexual only if you've actually had sex with both male and female partners? What about someone who has a fleeting homosexual encounter as an adolescent but never repeats the experience as a heterosexual adult? What about those who sometimes fantasize about having homosexual sex while they're making love to their spouse? (In fact, researchers have found that ihis is one of the most common fantasies of heterosexuals. )

Taking all this into account, Dr. his colleagues devised a seven-pm scale, later to become known as the Kinsey scale, in order to give a more accurate picture of the full scope of human sexual orientation. Thousands of men and. women were ranked on this scale after being extensively interviewed about their lifelong sexual experiences and their feelings of sexual attraction since puberty. At one extreme were people who were exclusively heterosexual, and at the opposite extreme, those who were exclusively homosexual. In between, there were five different categories to include everyone who might be considered bisexual to one degree or another.

After examining the resulting data, Dr. made this rather amazing pronouncement: "Since only 50 percent of the population is exclusively hetero¬sexual throughout its adult life, and since only 4 percent of the population is exclusively homosexual throughout its life, it appears that nearly half (46 percent) of the population engages in both heterosexual and homosexual activities, or reacts to persons of both sexes, in the course oftheir adult lives." Alex Comfort, M.D., Ph.D., in The Joy of Sex, goes even further, suggesting that "all people are bisexual- that is to say, able to respond sexually to some extent to people of either sex."

Still, if you define bisexuality a bit more narrowly and include only those people who have actually had sex with both men and women over a period of years and not just people who occasionally fantasize about same-sex encounters, only 10 or 15 percent of the population would qualifY, the Kinsey Institute recently reported. Interestingly enough, a number of different studies have also discovered that about twice as many men as women fall into this "in-between," bisexual category, although it's still not clear why. And as if to make the whole picture even murkier, other studies have shown that over 60 percent of adult men who consider themselves homosexuals and over 70 percent of adult women who consider themselves lesbians have at least occasionally made love with partners of the opposite sex.
And you thought you had it all figured out! (See also "Safer Sex.")