Homosexuality is a hot topic in today's world. More and more, people are willing to accept homosexual behavior and particularly same-sex marriage as a right and something that cannot be denied to people with these attractions. It is very well-known that the Catholic Church is opposed to same-sex marriage, and it is important to note that this opposition is not new. The Church has always taught that same-sex sexual relations are intrinsically wrong, even if a person has a natural sexual attraction towards persons of the same sex.
Condemned in the Bible
In the Old Testament, Genesis 19, the story is told of Sodom in which the male inhabitants of that city wished to commit homosexual acts with visitors of Lot. He did not allow them to, but God reigned down fire on the city because of their wickedness. Also, in Leviticus, God lays down a law against homosexual acts. “You shall not lie with a male as with a woman; it is an abomination.” - Leviticus 18:22. In the New Testament, St. Paul speaks out very clearly against homosexual behavior. “Therefore God gave them up in the lusts of their hearts to impurity, to the dishonoring of their bodies among themselves, because they exchanged the truth about God for a lie and worshiped and served the creature rather than the Creator, who is blessed for ever! Amen. For this reason God gave them up to dishonorable passions. Their women exchanged natural relations for unnatural, and the men likewise gave up natural relations with women and were consumed with passion for one another, men committing shameless acts with men and receiving in their own persons the due penalty for their error.” - Romans 1: 24 – 27. In this passage, St. Paul is very clear that such acts are unnatural and wrong.
Condemned by Early Church Fathers
The early church fathers were also very clear in their condemnation of homosexual behavior.
They recognized that it was contrary to the law of God as spoken in the Bible and that it was unnatural in human order.
He who is guilty of unseemliness with males will be under discipline for the same time as adulterers" – Basil the Great Letters 217:62
All of these affections (in Rom. 1:26–27)...were vile, but chiefly the mad lust after males; for the soul is more the sufferer in sins, and more dishonored than the body in diseases" – John Chrysostom Homilies on Romans 4
[T]hose shameful acts against nature, such as were committed in Sodom, ought everywhere and always to be detested and punished. If all nations were to do such things, they would be held guilty of the same crime by the law of God, which has not made men so that they should use one another in this way. – Augustine Confessions 3:8:15
[God in the Law given to Moses] having forbidden all unlawful marriage, and all unseemly practice, and the union of women with women and men with men. - Eusebius of Caesarea Demonstratio Evangelica 4.10
"Consider how great is that sin, to have forced hell to appear even before its time!… For that rain was unwonted, for the intercourse was contrary to nature, and it deluged the land, since lust had done so with their souls. Wherefore also the rain was the opposite of the customary rain. Now not only did it fail to stir up the womb of the earth to the production of fruits, but made it even useless for the reception of seed. For such was also the intercourse of the men, making a body of this sort more worthless than the very land of Sodom. And what is there more detestable than a man who hath pandered himself, or what more execrable? - John Chrysostom Homily 4 on Romans
These early Christian writers demonstrate their great disgust and horror at homosexual acts and condemn them as sinful. The opposition of the Catholic Church to these acts is not new, but stems from the Old Testament through the New Testament and 2000 years of history.