I've not read all the replies so sorry if someone has already said this, but I wonder whether those people asked were pregnant or considering children. Given that alot of people are having babies later in life I think that alot of Gen Y people wouldn't have yet considered children and therefore not be informed on anything.

I am Gen Y by only a few months and I am one of the first to have kids in my circle of friends who are mostly Gen X and haven't yet started to think about kiddies yet.