[quote="swimmingfreak, post:1, topic:246249"]
I am a supporter of gay marriage I myself at least I don't think I am because I'm fourteen. My point to this is why is it consider such a bad thing to do in the Catholic faith. God said he will except everyone, but then in the bible it also says (I think) same sex partners or something will burn in Hell. I don't get it because how do we have the right to say you can't love this person cause your wrong I think everyone should be allowed to marry who we want to and the church shouldn't have the right to send DVD's out saying this is wrong and marriage should "only" be between one man and one woman. (Minnesota had DVD's sent out to every house hold.) I probably won't change my opinion no matter what I am told I just want to know why the Catholic Church thinks it's so bad.
The Catholic Church's position on homosexuality stems in part from classical and medieval philosophy, specifically, natural law theory.
Natural law is based on classical essentialism, which holds that for every object in nature, there is a perfected "form" or "essence" in which it "participates" or "instantiates." You can generally grasp what the form of a thing is mentally, even if it doesn't occur in nature. For instance, you can conceive of a perfect triangle in your hand, even if it is impossible to draw a perfect one due to the minor imperfections that must be produced by the unsteady human hand.
Goodness, according to this theory, consists in adhering to the essence of a thing. So, for example, if a particular breed of dog is bred to be loyal and friendly (say, a golden retriever), a "good" golden retriever will be loyal and friendly; by contrast, a "bad" one will be aggressive or something. It's badness consists in the fact that it does not instantiate the essence of the breed very well. By contrast, a "good" guard dog would bark at the sight of a stranger; a "bad" guard dog would be very friendly even to unwelcome intruders.
This applies to people, as well. Specifically, the human sexual configuration (literally, that men have penises and women vaginas) exists to serve the purpose procreation. So does our strong sex drive and feelings of romantic attachment and romantic love. These are simply facts of nature. Because it is good to act in accordance with natural law, it is good that all sexual acts accord to the objectively procreative nature of the conjugal union.
This is how the Church derives not only its prohibition on homosexual acts but also nonprocreative sexual acts (such as anal sex or coitus interruptus), contraception, abortion, and masturbation.
The issue is not about love. Marriage serves the end of procreation, and romantic love serves that end as well. Thus, romantic love itself must be oriented toward the procreative act. Romantic love that is not so oriented (for instance, the romantic love between two people of the same sex, or between an adult and a child) is therefore deficient and disordered.
Hope that clarifies things for you.