The fantasy has become a reality. Between ads, movies, music, books and TV shows, society just can’t get enough bisexuality. As witnessed in the famous Madonna-Britney-Christina kiss and MTV star Tila Tequila’s adventures, society is fascinated by those who “bat for both teams.”

Bisexual pursuits have become so seemingly commonplace that one would think the world has gone “bi.” But the research on bisexual numbers paints a very different picture:

By all indications, true bisexual orientation is rare.

“Bisexuality refers to activities or inherent interests of an individual for sexual/genital involvement with both male and female partners,” according to sex researcher Milton Diamond, and that encompass people who are bi-curious or who are sorting through their sexual orientation.

But how many people actually identify as bisexual?

Good data on the number of bisexuals is scarce. Pioneering sex researcher Alfred Kinsey broke the mold in the 1950s in theorizing that bisexuality was much more common than believed. His research reported that almost half of the male population “engages in both heterosexual and homosexual activities, or reacts to persons of both sexes, in the course of their adult lives.”

But Kinsey's finding is considered highly controversial. The investigations conducted since have, like Kinsey’s research, been muddled by methodological issues. A number of issues -- for example, varied definitions of “bisexuality” and the problems with the sample -- have made it hard to establish the size of the bisexual population.

The stronger research efforts to date indicate that Kinsey’s numbers may have been off.

A 1991 Dutch study, based on a national random sample of 421 men and 580 women, found that only 13 out of 100 males and 10 out of 100 females admitted to having had a same-sex experience. Other studies out of Britain, Denmark and the U.S. have had similar results, all of which indicate that bisexuality may be less common than thought.

In the United States, a 2002 survey by the National Center for Health Statistics found that only 1.8 percent of men and 2.8 percent of women, ages 18-44, considered themselves bisexual. The Janus Report on Sexual Behaviors, published in 1994, found that only 5 percent of men and 3 percent of women identified as such.

Data collected thus far shows that most people are exclusively or predominantly heterosexual or homosexual. Most have sex for most of their lives, only with males or only with females -- but not with both.

Interestingly enough, the animal kingdom paints a similar picture. One finds that very few species show bisexual tendencies. This has been seen in female cows mounting each other (if a bull isn’t there to break up the action). The Bonobo, a chimpanzee-like primate, may dabble in same-sex play, for example, kissing and genital play, but this has been interpreted as tension-regulating functions.

Likewise, certain species of gulls have been reported as exhibiting female-female courting, mounting, and shared nesting. Yet these appeared to be due to a noteworthy shortage of males.

Getting back to humans ... It is rare for someone in any society to sustain an equal balance of same-sex and other-sex partners over an extended period of time, let alone a lifetime.

But that's not to say that people may not identify with bisexuality when it comes to their desires. It is not uncommon for a person to be coupled and to have fantasies that don’t match the orientation with which they identify.

In the 1980s, sex researcher Eli Coleman showed that while individuals tend to identify consistently as gay or straight, a number do not. When asked about desire, many rate themselves as bisexual, yet maintain gay or straight relationships exclusively.

These findings naturally beg the question: Are many bisexuals in the closet? That would, in some ways, explain society’s current love affair with bisexuality. Many people may be living vicariously through bisexuals in the media, since they can’t fess up themselves.

When processing any prevalence data, it’s important to remember that a number of elements may play into a person’s honest reporting of his or her sexual orientation. One’s social environment, political ties, and personal issues are just a handful of the factors that can influence how we label our sexual orientation and the types of relationships we have.

While bisexuality has existed in various societies throughout human existence, the term was coined in the 19th century. Despite the entertainment industry’s enthrallment with bisexuality, traditionally, society hasn’t rolled out the red carpet for this orientation. Its taboo nature is part of what makes it such a buzz today.

Perhaps, with the world now bonkers for bisexuality and the orientation coming out of the closet, we may get a better handle on how many bisexuals there actually are.

Dr. Yvonne K. Fulbright is a sex educator, relationship expert, columnist and founder of Sexuality Source Inc. She is the author of several books including, "Touch Me There! A Hands-On Guide to Your Orgasmic Hot Spots."

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