So I have to add my two cents, but I'll try to do it quickly.
1) This is not an argument about people's views on homosexuality. Even if you disagree with it, it doesn't justify taking away someone's rights. This is why we banned slavery, or gave women the right to vote, and it should be unquestionable.
2) This is also not an argument about anyone's religious views. First of all, your interpretation of the bible is your own. I am perfectly happy with the knowledge that God loves me, made me who I am, and that the bible says nothing against my lifestyle. None of that has any bearing on what rights I should be afforded by the government.
3) If a ballot ever comes up to allow people to marry animals, then we can discuss that. Until then, comparing gay marriage to bestiality is just ridiculous, and a really pathetic way to try to explain your own bigotry.
4) If you try to define marriage as in any way being tied to the act of procreation, then you're going to have a whole lot of people fighting you. Unless you're going to fight to invalidate the marriage of every infertile couple, childless couple, or anyone who's adopted a child, then you have absolutely no argument except, again, trying to misleadingly distract others from your bigotry.
5) Being entitled to have an opinion does not give you the right to take away the rights of someone else as a human being.
6) The male and female organs were not "made for each other". Please move on. I guarantee that there are a hell of a lot of things that you can either fit your **** into, or fit into a woman that you wouldn't consider being "made for each other". By that argument, a woman should be allowed to marry anything remotely phallus-shaped, and a man should be able to marry anything he can fit himself into. It also happens to conveniently avoid mentioning where God got the idea for the prostate, since that doesn't happen to fit that argument.
7) Please stop saying that homosexuality is "unnatural", I really don't feel like having to go back and dig up all the studies on how normal homosexuality is within just about every species on the earth.
Hope I didn't miss anything.