As far as I can tell, you are speaking backwards.
Being gay can not possibly be genetic because if it was, evolution would have removed it. Evolution is aggressive enough to remove traits that simply aren't necesary for survival, much less traits that are detrimental to passing on your genes.
Which is why we no longer have an appendix.
Oh, wait...
Humanity has any number of traits useless or even detrimental to survival, hard-coded into our DNA. And yet we continue to survive to breed and continue the species, despite it.
I wonder why it is a big deal. Joe, Jim, Karen, and Kimberly can already get married to any of the others. (Unless it is Joe, Karen AND Kimberly.) Any persons can get a ceremony and called themselves married. Except in the case of polygamy, the government will not step in.
What you seem to want is to use the force of government to make others recognize marriages. First, that is a very odd position for so-called "libertarians" to be in favor of more government coercion. Secondly, there are very specific reasons for the encouragement of heterosexual marriage through government policy, and none of those reason have to do with the welfare of the two persons engaging in that marriage. Homosexual marriage lacks the positive externalities that a stable heterosexual family has. Why should homosexuals recieve the government "benefits" without even the possibility of providing those externalities?
(Now, if you prefer the government to stop its encouragement of marriage, that is at least consistent with the libertarians' claimed position against the use of force. But, strangely, that's not what libertarians argue. They want more force used on the citizens.)
Nope - in all but a few states, Joe cannot marry Jim, Karen cannot marry Kim; to the best of my knowledge, in a large number of states which will not marry those couples, their marriage in states that WILL permit such ceremonies to be performed will not be considered valid (although there are more that will recognize those marriages than will permit them to be performed, AFAIK). Fedgov, holder of the tax purse, does not recognize the validity of those marriages (again, last I heard), while it DOES recognize my marriage to my wife. So your statement is factually-incorrect.
I have long advocated that government ought to get the hell out of anyone's sex life, to say nothing of their marriage. In fact, if I recall, I explicitly STATED that .gov shouldn't be involved in straight marriages either, in the post you quoted. Let me check... Huh. Look at that - "Granted, we need to get the government out of STRAIGHT marriages, too, but if we have to suffer their interference in the one, the other needs to be covered by the same blanket." Wonder what I meant by that?
Equal coverage of law is important, just as minimizing government interference is. Right now, our government gives BENEFITS to us straights as a result of marriage, and forbids access to those benefits to gays. THAT'S MORALLY INDEFENSIBLE.
You're not SERIOUSLY advocating that straights should continue to receive extra benefits under law so that they can continue overbreeding? Couples (or larger groups) would continue to have children regardless - .gov need not, and SHOULD not, be in the business of encouraging it in ANY way. And I would argue that a divorce rate in the 50% range seems to argue... strongly against the notion of the "stable heterosexual family" as something that the government is supporting. And yet, people are still having children
. So... got anything else to offer?
Good luck proving genetic causation WRT homosexuality (or any complex human behavior). I ran the numbers a while back and the sample size would need to be in the hundreds of billions.
Suffice to sat that barring some great & revolutionary mathematical/statistical breakthrough, no one can say, "homosexuality is caused by genetics" without being either ignorant or a liar.
Granted, I'm no statistician, but why would one need a sample size far in excess of actual existing population? And I'm pretty sure I stated that I was a layman and was expressing my belief about a major contributor (perhaps THE major contributor) to the maintenance of gays in the human population despite the fact that, overall, they don't breed. Could "nuture" result in a fairly-constant gay population in a heavily-majority-straight population without a genetic component?
Dunno. But I really don't THINK so. Am I going to sit down and prove it mathematically/statistically? Nope. I just think they ought to be treated same as me and you, and wonder why so many have a problem with that.