It really doesn't matter whether or not one believes homosexuals were born that way. Agreeing that there might be a genetic factor to homosexuality is not the big "gotcha!" that homosexual activists think it is -- at least not for Christians. After all, Christians believe we are born in sin. We are all, in that sense, "born that way." For some people it's homosexual acts, for others lying, and for others adultery.
But just as the liar can't claim God doesn't mind his lying because he was "born that way," neither can the homosexual claim homosexual acts don't offend God.
I completely understand and agree with this view. However, I know no person who, and I'm sure there may be some, and they may be 2% of the population as well, who claim that lying and adultery are good, righteous and true morally and are unrepentant for these sins. It's kind of a claptrap to put some sins on equal footing as others...IMHO.