Yeah we sort of established that the government is stupid and wrong and that homosexuality isn't a disease. But nice find. You should see if GLAAD knows about it.
rabbit, no, we haven't. We haven't established whether it's genetic (nature vs. nurture), and if it's not genetic, whether it's nurture vs. choice.
We haven't established these things because there have not been controlled, conclusive studies about them. Show me the university study where they tried to raise someone gay, or they cross-bred gays and lesbians for several generations to see if they became gay.
Even if it was, who are you to say it is an "imbalance"? Couldn't we say that homosexuals are normal, it just so happens that the majority of the population of "chemically imbalanced"?
If it was a naturally-occurring imbalance, this tendency naturally selects against the homosexual population. Evolutionarily speaking, it is abnormal.