I wouldn't be too sure about that. In the first place, as a Christian who reads and believes in the Bible as the Word of God, I can find nothing scripturally to support that God creates a person to be a slave to what HE calls a sin. I don't pretend to understand the whys and wherefores of much that God does or allows, but I do know that He does not allow a temptation without a means of escape because He says so and He cannot lie.
"There hath no temptation taken you but such as is common to man: but God [is] faithful, who will not suffer you to be tempted above that ye are able; but will with the temptation also make a way to escape, that ye may be able to bear [it]. (1 Corin. 10:13)
It isn't like a child born with a disease or deformity. These things may, in fact, have a genetic component, but are in no way condemned as sinful. A person may even be born with a genetic predisposition to alcoholism because of the way in which his body processes alcohol. Is the predisposition a sin? Of course not, but being a drunk is, and an alcoholic is no more excused of his behavior because of that predisposition than anybody else who who drinks to excess.
In the second place, just suppose that science "proved" the existence of a gene that predisposes toward homosexuality. Given today's political climate, do you really think for a minute that the queers would sit still for future queers being eliminated? That would be predicated on the fundamental assumption that homosexuality is abnormal, which is exactly the opposite of what they're putting all this energy into making you believe. No, I think it would give them political carte blanche to actually "select" FOR it, breeding little genetic mutants in petri dishes to be implanted in host mothers. It has fallen to us at this point in time to change the direction this ship is heading and if we fail to do so, I truly fear for the world our progeny will inherit.
Why? By your own words, you know that He who is all power knows already our plights. It is up to us to accept (i.e. not judge!) the world and it's problems (including our own shortcomings) in preparation for the next life.