I never knew one child in my school years that had a nut allergy. Now it seems 1/4 of the kids in my grand's class has one. I think waiting too long for a child to be exposed to nuts,dairy, wheat, whatever, tends to have the body react to the foreign food in a harsh way. My kids got a tiny taste of peanut butter at a young age and every month after a bigger taste. Same with eggs. Kids of past generations were eating every day table food by the age of six month so I think the body adapted to handle it in the majority of kids.