I have some friends who have never masturbated, we're all around 23 now. I find that a bit weird, since I started when I was 11 and it has been a natural thing since. But they find ME weird for starting so early. :P One of them said she just didn't know how to do it. It's not really rocket science, just touch yourself until it feels good... :P If they don't have an urge to do it, I don't understand why they should do it. But I also think a lot of women seem to be more inhibited about this, feeling that it's wrong or embarrassing or afraid they're doing something wrong or whatever. Which in my opinion is a shame, it's completely natural.