I broached the subject:
"Just how human are you?"
"I'm not human at all."
"You look human."
"Yes."
This was going nowhere.
"What I mean is: how similar are Time Lords to humans? I know you've got two hearts, while we only have one. And you don't need to sleep as much as we do. But you're obviously capable of love…"
"Yes. I am capable of that."
"Sooo." How to go on? "Are you capable of…"
"Physical love?"
"Yeah"
"Yes. I'm capable of that, too."
Well, as it turned out, he was very capable. If a little out of practice.