Question for those who used donor sperm

I wasn’t sure where to post this. For anyone who used donor sperm, maybe particularly those in a same sex relationship or SMBC, what will you call the sperm donor both to others and to your child? I’ve had some people ask about my son’s “dad” (I’m due in October) and that feels weird to me. When people ask questions, I refer to the donor as the donor, but people always try to correct me and say “his father, you mean.” But no, I don’t mean father. How are other mommas handling this? Thanks!