I've kind of made Jack a hero that I would like to have looked up to as a little boy because as a little boy, I knew I was gay but I didn't know what it was. Didn't know who to talk to about it. … I wanted kids to like him, and I wanted women, men, I wanted everyone to like him. But first I wanted people to hate him. I wanted them to think he was arrogant and pushy and too sure of himself. And I wanted them to follow the arc of the change he went through in the final episodes of Doctor Who.
On Jack Harkness, in "Fall TV Preview: Captain Jack (not that one) talks about the gay barrier: in seattlepi (16 July 2007)