Mrs NOP (sorry about the hijack, ZB, but I think you are probably interested in the answers too, so I'll keep it here) Anything sexual at all is taboo. She'll walk out of a room if her friends are talking about sex. She skips over the sex scenes in novels and turns away from sex scenes in movies. Any discussions about anything sexual are very uncomfortable for her. She gives short non-answers and changes the subject. So, while it isn't a flat out refusal, it is acute avoidance of the topic. Extends to talking about sex to the kids too. Does that answer it? Any thoughts to making it easier?
