Wiktionary
birth father
n. The genetic father of a child (as opposed to an adoptive or stepfather)
Usage examples of "birth father".
Or maybe my birth mother was Japanese and my birth father was American, and I had my mother's features and my father's last name.
He thinks it's to vet the birth father, to make sure his stepson won't get hurt, if and when the two finally meet, but he discovers on the trip that it's also a way for him to reconnect with his own father.
He knew his uncle far better than his birth father, who had drowned when Muller was seven.
It's conducted in utero with the birth father in bed with Fertility and his wife waiting outside the door.