In the case of the 35/13 situation, there is a huge factor present that isn’t in the same-sex wedding. In the 35/13 situation, the 35 year old is a despicable person because he is preying on a child who is not able to give consent. So the issue then becomes, do you stand by and witness abusive behavior in this way? A same sex relationship of consenting adults isn’t abusive because it is a same sex relationship of consenting adults.
As you stated, you find an adult man marrying an underage girl to be problematic in a different way than a same-sex union would be problematic. That’s fine, and that’s what I expected, based on your previous posts. But my point is that I think you agree that there could be
some wedding situation (for you it would be an adult man marrying an underage girl) that is problematic to such a degree or in such a way (in this case, because the man is “preying on a child who is not able to give consent”) that you might choose not to attend the wedding, even if it is the wedding of your own son. Let me know if I am putting words in your mouth, but that seems to me to be a fair summary.
Assuming that I am not misrepresenting you, then I think we are at least somewhat on the same page. It seems to me that we both see that there is at least some wedding ceremony that we might choose not to participate in, even for our own children. As I said in a previous post, my list of such scenarios is probably longer than yours, but the principle is the same.
And for my part, I believe that a homosexual union is every bit as problematic as a 35-year-old man marrying a 13-year-old girl – perhaps even more problematic. Yes, it is problematic for different reasons, as you stated. In one case, the problem stems from consent, and in the other it stems from natural law and sexual morality. I’m not expecting you to agree with my reasons, but that might help you to understand where I’m coming from in saying that I wouldn’t attend this type of “wedding.”
In summary, I think that we both agree that in certain difficult situations, a parent would have to balance the desires to be there for a child’s special occasion and not to alienate the child, with the desire not to support something that is gravely immoral or harmful. We definitely disagree strongly on the prudential question of how to balance these two sides in certain specific situations, like a same-sex “wedding” ceremony. We may even disagree on whether homosexual acts qualify as gravely immoral or harmful. But I think we can at least agree that there are times when a parent must weigh those two sides and make a decision, and that either decision (to attend or not to attend) could be a valid one, at least in
some situation(s).