It is worse than that.
If a "gay gene" is ever isolated, you can be sure that these couples will replenish the supply of new gays by genetically engineering homosexual fetuses.
I admit that is not a possibility I had considered. Yikes! :) I think I'd rather rest in knowing that God's Word prevents the true discovery of any "gay" gene dooming those having it to a life of homosexuality. God never says that being white or black, or tall or short is sinful. I think God only talks about chosen behavior as being sinful.