This is one of those pieces of info I try to slip in whenever possible. I'm a firm believer that celibacy is bad for the mind, body, and soul when it's forced on people. Priests may go into it willingly, but years and years of it with no reprieve does bad things to people's minds. If the church could make one reform that I genuinely believe would be best, it is the celibacy of clergy. Tons of reforms needed, but that one is the one I think needs to happen soonest.

Then they should be happy with same sex marriages. A miracle might occur with them just as well.

Again, I'm reasonably certain they don't actually believe a 90 year old woman is suddenly going to get pregnant, or a woman who doesn't have a uterus anymore, or whatever else. These might be the words they're told to repeat to justify things, but they don't believe them. Not even the most devout would believe that.

They may believe God could technically do this, but then he could also technically do the same for same sex couples. He's omnipotent, according to them, after all. His powers are not limited to only making miracles pregnancies to hetero couples. It's no more outrageous than expecting people physically incapable of becoming pregnant becoming pregnant. If they justify this belief based on miricles, then same sex marriage is equally justified. (This is not their belief. They don't believe the former premise, but this is the conclusion that it'd lead to.)