Possibly. See S3E4, "Daleks in Manhattan"." the Doctor, when reunited with Martha and their contemporary friend Frank in the sewers on the way to Dalek Sek, tells Martha that she can kiss him later. He then adds that Frank may do the same if he likes.
Also see Steven Moffat's twitter response to a question asking how the Doctor cannot know the difference between gay and straight. "He comes from a world where such narrow views [of sexuality] seem so ridiculous they're hard to remember." <https://twitter.com/steven_moffat/status/200839207386746880>