"How would he have a girl self?" - look at the Master/Misstress. And what about the time that David regenerated into Matt who initially thought he was a girl? "Then he can't be married to SPOILER" - who says time lords can't have gay marriage?
The doctor isn't a person, he's a timelord, but still, he's a boy. Timelords have genders. How could his parents give birth to him then? *spioler* is a girl and when she regenerated stayed a girl.
"Then he can't be married to SPOILER" - who says time lords can't have gay marriage?
Sorry