This is something I've been pondering myself recently, the leading scientific opinion is that jomosexuality is based on biology rather than being a choice, but I still wonder. I think Nature vs Nuture comes into play. Just wondering what others thoughts are.
The only kind of homosexuality that even deserves a scientific investigation for possible genetic determination is one where they cannot reproduce because of their choice of mate. Investigation into every other kind is politically motivated pseudoscience for which I don't have much use.
"Homosexuals" that enagage in procreative sex and reproduce, from an evolutionary point of view, are no different from people who masturbate or abstain from sex when no mate of the opposite gender is available. Essentially such behaviour is of no evolutionary consequence. Any of them could be caused by genes, but no scientific-minded person would expect them to be genetically determined let alone looking for evidence of genetic causes for such behaviour.
Something is biologically determined doesn't necessarily mean it is genetically determined and hence inheritable, although the converse is true. There are many biological factors besides the genes that determine an individual at birth. So while it is possible, although unlilkely, that preference for homosexuality, masturbation and celibacy are biologically determined, it is extremely unlikely that they are genetically determined.
The well-meaning people who insist on genetically determined homosexuality and even manufacture evidence to support such a claim don't realise the bigger problem they are creating. Those who discriminate against gays and insist the law too discriminate against them don't care whether homosexuality is a choice or biologically determined. They believe it is wrong and people should not engage in it, whatever the cause, biological or choice. They would prefer such people, even if biologically conditioned, to masturbate or remain celibate but not engage in homosexual behaviour. So "scientific" claims that it is genetically inherited, if it becomes popular belief, while not making the homophobes tolerant of homosexuality, instead will make every relative of an openly homsexual person to be suspected of being a likely homosexual, who probably is "yet to come out of the closet". So you will end up with straight relatives of homosexuals being looked at with suspicion for potential homosexual behaviour and may end up failing to attract any member of the opposite gender into a relationship, making their lives frustrating. A cure worse than the problem. Inappropriate social attitudes must be fought on social platforms. Science should not be manipulated to serve political agendas, for you do not know exactly what you will get when you do so.
"The only kind of homosexuality that even deserves a scientific investigation for possible genetic determination ..."
This statement is just wrong. We just don't know whether it is genetic, a combination of genetics and environment, purely environmental, or "just a preference". Until it becaomes more clear, a number of avenues should be persued, if only to rule some of them out. As a former physics researcher I think you make a number of erroneous statements about science research.
"but no scientific-minded person would expect them to be genetically determined "
That's one. Numerous reputable and well-regarded researchers have valid reasons for suspecting genetics as being at least partially involved.
Let's just say, for the sake of argument, that we discover a gay gene or genes. Then there will no doubt be some ethical questions arising from this. I would be willing to bet that many of the anti-abortion groups here would be torn between wanting to allow the abortion of "gay fetuses" and sticking with their current stance. Others would want to pre-select "straight embryos". Some might start using the knowledge to look for a "cure". All of these things would be wrong, in my view. However, just because reasearch results and discoveries can be misused doesn't necessarily mean the research shouldn't be done.
I am a former researcher myself and know exactly what criteria are used to start an investigation.
No one would start an investigation into whether homosexual preference is biological much less genetic, out of pure academic curiosity anymore than they would a preference for masturbation or celibacy.
Even if someone was curious, since homosexuality is not restricted to the human species, why would they pick a species for study where the definition itself is fuzzy and not directly verfiable while they could pick species like mice to perform controlled experiments that are readily verifiable by others?
Whatever the social consequences, I don't object to honest and academic investigations. What I was cautioning against was well-intentioned but dishonest and politically motivated investigations claiming to be scientific and whose only purpose is to justify a political agenda.
If you are not a position to separate what is politically motivated BS from what is actual scientific research and have to depend on the number and reputation of the scientists to believe one way or another, I am sorry. But I am quite capable of distinguishing one from another for myself and don't really need to depend on the number and reputation of scientists who favour one view or another. This genetically determined homosexuality is pure BS.
I eagerly look forward to your receiving the Nobel prize for medicine for your seminal paper "I assert that a genetic cause of homosexualityis BS" :-)
No has yet identified a 'gay gene'. So talking as if its existence is undisputed is jumping the gun.
First, there is no such thing as a "gay gene". At least, there isn't any specific thing we know of that could conclusively be called that and fit in with what we know about genes and how they work.
Second, gay individuals have always had the ability to procreate, in nature or otherwise. But evolution works in populations, not just individuals. Heritable traits can be passed down by other relatives. For example, gay men never need to procreate to have their genetics passed on when they have sisters who do so for them (gay uncle theory?). A great example of this is bees. Only the queen passes on her genes with the support of the hive.