I was asked as a scientist why I think gay marriage is wrong. The following web pages provide a more definitive answer in medical terms, therefore elaborating on one aspect of my original answer. As a scientist I am reality based in the natural world and as concerns my faith. I don't think that a lie is right for instance. I think NaCl is the chemical symbol for salt as an example. I do not see a conflict between the truth of natural things, morality, ethics, and spiritual matters. I may say that NaCl is really gold, but it won't make it so.
Now, we have before us a man who is gay that is a Bishop in the Episcopal Church and openly touts his opposition to God and the Bible with many supporters in his denomination as well as many more outside Christendom. He left his wife and children for a gay lover and committed adultery with this man openly. His church is now openly apostate. To them I can only say Anathema, Maranatha. Some of us who believe God and His Word are able to speak up and do so. The same church has decided to bless same sex unions that are an abomination before God. These people are advocating the practice of evil. Evil has become protected as a matter of law in the United States. There is no place on this planet besides the United States, the Netherlands, and Canada that has made the practice of evil at such a primæval level a matter of forced acceptance by the rule of law. It is not obvious to many that the gay lifestyle is extremely destructive physically and mentally. That has important implications for the commonweal. The decision to reward evil that has been judged by God and revealed to us is a mistake. The decision to teach others to do the same is more grave that rewarding evil. The decision to judge God and His Word is anathema, an accursed thing. I am glad I am not among those who advocate our country becoming an accursed thing, something that is designated as an object of destruction.
The following article on the next few pages touches the surface of why the gay lifestyle is harmful. It is from a web site that has been reformatted that was originally produced by the friends of Bishop Sean Manchester. It is a wonder to me that anyone in the church would advocate living in a way that is harmful and glossing over the harm that it brings.