Not a new problem. I believe the answer is to list the father as "unknown". These people are trying to create a problem that doesn't exist.
“These people are trying to create a problem that doesn’t exist. “
They are crazy people. The one thing crazy people can’t put up with is people who see a different reality than they see. They will force those others to see the same reality. This is how they make their own reality real. If they fail, then the fantasy world they are trying to live in breaks down. It would be like finding out instead of standing on rock you are standing on Jello and in danger of falling. When you fall it is the same as dying. So, you will work hard on convincing the world that you are standing on rock.
I was at a dinner party where a few gay guys were attending when their marriage bill was defeated in Florida. One of them went absolutely apeshit crazy. He threatened to go out instantly and commit violence against some people who were visibly on the other side of the issue. (Thank goodness they weren’t there.) The only way to deal with people like that is to get them out of your life. I never attended another party or even spoke to the other people I had met there.
Unfortunately, once the courts are involved we don’t have an option just to avoid these people. They are using the enforcement arm of society to make people bake their cakes and give them corroborating paperwork like marriage licenses. The scary thing is, they can’t declare victory and just be satisfied with a few wins. They must keep on until they have remade the world into the image they fantasize is real.