As a molecular biologist, I agree that most of what we are going to read in popular press about "found genes" is going to be sound bytes that do not mean anything in themselves. I am reading an excellent book right now called
Brave New Brain (Nancy Andreasen). In one chapter, she explains in an accessible way the methods, practices, and problems of locating genes. Many diseases are "complex", and cannot be explained by one gene. Also, genes are more flexible than you would think. An example of a complex disease is cancer.
Mental and behavioral diseases are though of as complex, with VERY few exceptions. Progress may be made, but the goal of disease research is to help people that are in distress, not to prove that anything is "genetic". Homosexuality is not a disease, only Sexual Orientation Disturbance is a disease. The Amercian Psychiatric Association has not considered Homosexuality a disease since 1973, when they
changed the entry in the DSM-II (Diagnostic and Statistical Manual of Mental Disorders). Short, recommended reading if interested.
I wouldn't make any generalizations about whether gays
want there to be a genetic basis or not. There is a pretty good reason for that particular group to not want it.. its called eugenics, some would say its the concept that was misused by Hitler. The idea behind eugenics is that we can breed out genetic impurities (diseases). Eugenics also had a bad run in the U.S., with forced sterilization of thousands of women of "weak character". James Watson, a co-discoverer of the double helix structure, is a current proponent of eugenics (is trying to clear its name of the bad associations). He thinks we should use eugenics to give parents more choices, and to make prettier women.
*edit: spell