Of course he hasn't.  Liberals throw up things like rape, incest and health of the mother all the time in the discussion.  Those are Red Herrings.  Those who are pro-abortion would not support anti-abortion legislation if it took into account rape, incest and health of the mother.  Therefore they are not relevant to the discussion.  

Perhaps it would help when debating these people to narrow the discussion to abortion on demand so they can't get away with that.