How Could Mary get Pregnant If God Was Not a Man?

An excellent question! The incarnation of Jesus is not bound by human biology. So we are talking about a supernatural event that we are trying to limit by our own natural biology.

That said, Jesus was indeed both human and divine. So it is not important to emphasize the biological necessity of a male donor, but rather the emphasis is on the divine one entering into humanity through our human birth to a woman. Does this happen by a male sperm uniting with a female egg. Almost certainly, but not necessarily. It is a true mystery of our faith with regards to “how” this all happened scientifically. The faith element of this event is what we need to emphasize here. The point of the story is that God entered into our humanity and the gospel writers probably knew little about human biology and therefore we don’t hear much about how this divine creativity works at the level of science. Instead we trust that God took care of the biological process and cared enough about humanity to become like us and to enter the world as one of us and shared in our death, although God did not need to do so.

God is neither male nor female, but in order to enter humanity God chose to become a baby and to be born of a woman, a virgin. That is the important piece of information that the gospel writers chose to communicate. I applaud your inquisitiveness though and pray that we can allow ourselves to allow ourselves to trust that God used human biology in some way–although the writers of antiquity could not explain how that happened.