Aside from whether there would be anything wrong with that, it begs the issue of what leads to homosexual orientation. The RR presumes that it's all some Evil Perverted Choice that people make, and that once it stops being considered evil and perverted by society, then more people will make that choice. That seems to fly in the face of what the vast majority of gay people say about their sexual orientation not being a choice, but — well, an orientation, something that was just there (speaking from this side of the aisle, certainly I never made a conscious choice to find women sexually attractive, so I presume the same is probably true for gays).
That all said — I think the gay and bisexual population will increase by some margin once gays become more accepted. Because there are a lot of people who are living a lie, who try to pass as straight, who try to convince others (and, in some cases, themselves) that they are not gay. They do this from shame and an upbringing and society that says that homosexuality is Evil and Perverted and Anti-God and Anti-American and the Worse Thing Ever. Change that, and I strongly believe that more people will accept their already-existing same-sex attractions. It won't produce more gays, but more gays will be willing to be out, to others and/or to themselves.
(In a similar way, to take on Stewart's quip, whites didn't decide to be black, but some blacks who were trying to pass as white didn't need to and thus could stop or, in later generations, never start.)
So, to that small degree, the Religious Right is correct. The gay population, both visible and those willing to act on being gay, will increase incrementally as being gay becomes accepted. They're just dead wrong about it being a great national tragedy. I think it will be anything but.
(h/t +Paula Jones)
Reshared post from +Don Denton
If gays become accepted, then more people will decide to be gay.
