There are fewer genes which directly affect the phenotype (such as G6PD deficiency, cystic fibrosis, sickle cell anemia, Tay-Sachs disease etc.) for most phenotypes are affected by the function of the multiple genes. For instance, there is not one gene that is related with the height of a person, or their complexion, or their hair color, or their intelligence, or diseases such as diabetes, cancers, cardiovascular etc. Most congenital phenotype are a result of the deletion or addition of sets of genes and that only happens when large chunks of chromosomes are either deleted or added (such as the Down's syndrome or trisomy 21). The science has yet to find a gene or sets of genes that are directly related with the gender of a person or at-least gender preferences when it comes to certain intimacy calls.
I am not at all disputing the effect of social circumstance and upbringing on what a person feels or not feels, but rather the possibility that particular genuine cases do exist. Take bisexuals for instance, there is no other plausible reason other than sexual over-activity for their behaviour; they just aren't satisfied and resort to unnatural behaviour.. or rather pleasure seeking choices. There is little rights involved there and as such their preferences are as beyond the norm as incest or other deviations. The people that are in actual trouble in our context are the transexuals or euncuhs. Whilst arguing that brain development too itself may have an effect regardless of how the rest of the body develops.
Transsexual differences caught on brain scan - life - 26 January 2011 - New Scientist
The issue here is not legitimizing sodomy for those seeking it as a life choice, but rather those who were hardwired from the start for it. To take a crude e.g. Take the son of a WANA operation veteran and land him in the midst of eunuchs, see if he does not develop into one. The same way, take a small boy taken in by Eunuchs and put him straight out into cadet college and further on, see how he does not develop into a hard core fellow.
However, take the same boys and try reintroducing them into the societies they came in from and the process to convert them back would be impossible regardless of whatever hormonal therapies ensue. Those that have had a lifestyle that has changed them into what they are cannot be entirely blamed for their choices. At least not those who have had an entire adult development cycle that changed them.
As for those whose brains were hardwired to develop that way, we cant blame them at all or shun them out of society.
There is a spread of deviancy, just as there is mistaking disabilities for deviant behaviour. Society itself is at fault for allowing such prejudices to ferment. The article posted reeks of hypocrisy when it talks of ET talking about the so called LGBT community(who in many cases are basically the results of social upbringing and very few genuine cases) when they ignore Eunuchs, and the much less spoken but widely known habits of "bacha/londa bazi" prevalent in our society. So while the attention seeking desires of LGBTs aside, our society itself is, to use the most appropiate word; beghairat in that it will create a fuss over two girls rebelling against perverse social pressures and making out whilst quietly shoving up the various acts of sodomy that occur across our rural and urban societies within places such as Truck stops to more sanctimonious Madressahs and Public schools.
Quite frankly, whilst finding both disgusting.. I would not be threatened by two girls(or guys) from generally affluent families choosing their sexual preferences as compared to the horror of someone being sodomized by force.