Boe is a "he" who can have babies and his species is never identified. Let's not forget that it was suggest that Captain Jack might be the face of Boe.I liked the episode. Doctor is saving lots of people this season. Davros, himself with paradoxes, Ashildr.
But did anyone notice the book the Doctor was flipping through? Not his Diary. There was a book in one of the Viking's rooms which looked like something from a few hundred years hence.
Face of Boe.
Boe is male and a different species
That might just be what a human look like after million(s) of years of being killed and coming back to life. Maybe there were times he was really too messed up to heal properly.