...very well presented and, almost, completely flawed.

There is not one word in that well written article which can actually be shown to be true, in other words, proven.

There is no absolute scientific proof that gays are born and there is no absolute scientific proof that they are created. There are indications, theories, extrapolations and plenty of guesses but no proof...for either side. How "gayness" happens is still open for conjecture. I imagine there is more than one way.

There is scientific proof that they do exist now and have existed in the past. We can speculate that there will be gays in the future and that there were gays in prehistory, but we have no way to prove that.

Those articles state opinion, which is just fine since everybody is entitled to theirs. Just don't confuse it with proof.