This is a very complex issue. It’s not as simple as people on both sides of the aisle want to make it. There are some basic principles that do help us understand what is right and wrong. Many people are not educated in these principles.
First: God reveals himself. He discloses himself to man through Sacred Scripture, also through sacred tradition, the Magisterium of the Church, natural law, and logic.
We can’t just throw a bible verse at something and pretend we have it all figured out. All of these pieces must work together. They are all good, because they all come from the same divine origin.
Second: Faith enlightens reason. We must reason through these questions and let our faith inform us whether or not our reasoning is consistent with what God has revealed about his nature and the nature of man.
Third: People have to distinguish between the action and the person. They are not the same. When a five-year old kills his little brother with his father’s gun during a game of “cops and robbers,” the action is contrary to the commandment, “Thou shall not kill.” However, the five-year old is not a murderer, because he neither intended to actually kill his sibling, nor is he knowledgeable of the commandment. The action remains evil; but the child is not culpable. We can condemn behaviors, but we have to be very careful not to judge people. That would be playing God.
Fourth: Judging another person involves walking through his or her mind and conscience. One’s thoughts on any issue and one’s moral conscience are part of what is known as the “internal forum”. This is an area of human existence that no human being may trespass or attempt to read without an invitation from the individual who is the lawful guardian of his mind and conscience. We can explain why a certain action or behavior is wrong, but we may not pass judgment on the individual’s moral reasoning unless that person invites us to examine it with him, thus inviting us into the internal forum.
Fifth: There is a big difference between homosexual acts and homosexuality. A person with same sex attraction does not wake up one morning and decide to be gay. As he develops and goes through different life experiences, he becomes aware of his feelings in this area. On the other hand, people freely choose to engage in sexual behavior with a person of the same sex. Choosing to be attracted to the same sex is very rare. That which man does not choose can be neither a sin nor a virtue.
Sixth: Homosexual acts, like heterosexual acts, are freely chosen by the parties involved (except in cases of violent force). The person(s) must use reason to determine whether an act is right or wrong. If the person is a man or woman of faith, that faith should confirm the correctness of his conclusion or point to its moral error.
Seventh: Acting on faith and basing our actions on what God has disclosed to us about him, about us and about the relationship between the divine and the human is not the same as playing God. It is using that which makes us in the image and likeness of God to make right choices, that being knowledge of right and wrong.
Eighth: Standing in judgment of an action does not constitute godliness. It’s part of human reason and part of living in society. On the other hand, standing in judgment of the person involved in the action that we reject, IS playing God. No one has the right to judge the conscience of another human being, unless the other person opens up his heart and shares what is on his conscience.