When the American Psychiatric Association (APA) decided in 1973 to remove homosexuality from its list of official mental diseases, many psychiatrists were outraged. They demanded a vote of the full APA membership. Think about that. Is that how questions of science should be decided—by a vote? But the whole question of homosexuality had become so politicized, so emotional, that the psychiatrists could not even see the implications of what they were doing (Bayer, 1981).
For 100 years or so, homosexuality was considered a sickness. Only when scientists dropped that assumption did they make real progress in understanding homosexuality. The enormous complexity of the human brain allows highly flexible human behavior patterns in almost every aspect of life, and human sexuality is not an exception to that rule.
Theories of sexual orientation change as society changes. Our society is grappling with its acceptance of new forms of sexual relationships. Only time will tell whether that yields increased tolerance or intolerance for people of all sexual orientations.