The discussion of sexual orientation is complex and emotional. It is complex because it encompasses a wide range of scientific fields such as behavioural genetics, neuro-anatomy, psychiatry, psychology, sociology and many others. And it is emotional because sexuality is such an integral part of our identity as individuals. Homosexuality has undoubtedly been one of the most debated socio-political topics in the west over the past few decades.
There are two main kinds of studies that are carried out regarding sexual orientation. They are usually referred to as the nature vs. nurture arguments. This concept is not restricted to the question of sexual orientation only but is widely used in science. It basically asks – “to what extent is something the way that it is because of its biologically inherited nature, such as genetics?” And, “to what extent is something the way that it is because of the way that it is nurtured, otherwise known as environmental factors?” This includes the influence of hormones on a baby during pregnancy, how the child is nurtured by the parents and the subsequent relationship with the parents and peers as the child grows up, as well as the experiences that the child has.
It is necessary to mention that even though the idea of a so called ‘gay gene’ has been popularized by the media, there is not a shred of scientific evidence showing that homosexuality is genetically determined and therefore immutable (unchangeable). That is not to say that studies to prove a genetic cause have not been undertaken. Many studies have been undertaken by research professionals from respected academic institutions. Here are three famous ones:
1. Geneticist, Dean Hamer, author of the ‘gay gene’ study tried to link homosexuality to a string of DNA on the X chromosome called Xq28.
2. Simon LeVay, a neuro scientist, studied the differences in the front hypothalamus (INAH3) part of the brain of homosexual and heterosexual males.
3. Bailey and Pillard did studies on identical twins that had 100% the same DNA, non identical twins, siblings and adopted siblings of the same sex.
None of these studies or any other subsequent studies have shown that homosexuality is genetically determined and therefore immutable (unchangeable) and neither do they make that claim. The majority of respected scientists now believe that homosexuality is attributable to a variety of complex factors.
Dean Hamer said “There is not a single master gene that makes people gay…I don’t think we will ever predict who will be gay” 
Simon LeVay, the author of the hypothalamus study, noted, “It’s important to stress what I didn’t find. I did not prove that homosexuality was genetic, or find a genetic cause for being gay. I didn’t show that gay men were born that way, the most common mistake people make in interpreting my work” 
Doctors For Life International affirms that people who have a same sex attraction have the right to seek professional help and that therapists have the right to offer it.
In reviewing the research, psychiatrist Jeffrey Satinover reported a 52% success rate in the treatment of unwanted homosexual attraction. 
Masters and Johnson, the famed sex researchers, reported 65% success rate after a five-year follow-up. 
 Mitchell, N, (1995). Genetics, sexuality linked, study says. Standard Examiner, April 30.
 Nimmons, D. (1994). Sexual brain. Discover, 5, 3.
 Satinover, J. (1996). Homosexuality and the politics of truth. Grand Rapids, Michigan: Baker Books.
 Schwartz, M. F. & Masters, W. H. (1984). The Masters and Johnson treatment program for dissatisfied homosexual men. American Journal of Psychiatry, 141, pp. 173-181.