Re: Who would you like to portray the 12th doctor?
I don't see any reason why some Timelords can't be explicitly male, some always female and others more variable. Similar variations on gender and sexuality exist in our species. I certainly see the Doctor as being pretty solidly male, which is emphasized by moments like 11's first scene when he seems genuinely surprised that he might be a girl.
"There is no reason why good cannot triumph as often as evil. The triumph of anything is a matter of organization. If there are such things as angels, I hope that they are organized along the lines of the Maffia." - Winston Niles Rumfoord.