Bisexual: Are bisexuals "fifty-fifty"?

General Knowledge

Three particular sets of circumstances have been thought to be conducive to bisexuality:

Sexual experimentation in a relationship with a close friend is quite common among women and can also occur between two male friends or a male homosexual may develop a sexual relationship from a previously casual but friendly relationship with a woman.
Group sex is another avenue for bisexual experimentation.
Finally, some people adopt a bisexual philosophy as an outgrowth of a personal belief system. For instance, some women who have been active in the women's movement find they are drawn closer to other women by the experience and translate this closeness into sexual expression.