I once interviewed with GE for an engineering position and the interviewer asked me if my dad was dead. No lie. I think he was trying to shock me or something.
Some personal/family questions have no place in an interview regardless of legalities. Religion and politics come to mind. A married Catholic Republican may not be any better than a divorced Methodist Democrat. Has no bearing on his/her ability to do an effective job.
Alot of your questions should be submitted in a job application form before the interview to save each of you some valuable time. For $20-$30 bucks you can buy a very good job application form on line.