He isn't saying you shouldn't have an opinion, but that you won't _get_ it until you are a parent. I am not a parent, but I can understand that I DON'T know what if feels like until you are. I didn't know what love was until I had a long term girlfriend, and I didn't know what love really was until I broke up with that girl and found the right one, even though I thought I did. So I think it is reasonable to extend that to - you have no idea what it feels like to be a parent until you are one. The pool of parents is so large I don't think you can make broad generalizations, I think a lot of it has to do with the stress of paying for kids so breaking it up by class would be interesting.