I refused to give my kids cow's milk to drink until they were at least 2 years old. I even battled with my pediatrician over it. We have a family history of cow's milk allergy/intolerance. I didn't want to risk dealing with ear infections and such. It turns out I was right. Score one for the mother-gut!
We just had my 6yr old blood-tested for allergies. Sure enough, she showed a mild reaction to milk. Which, according to the ENT, means that she
has antibodies to cow's milk in her system. I'm VERY thankful that I recently stopped allowing her to drink milk. I shudder to think of what her antibody level might have been if I'd been letting her drink milk every day.
At the moment, I still allow her to have
some dairy, like string cheese or sliced cheese, but nothing else. Most palatable yogurts have too much sugar in them or are artificially sweetened, so they're out, too. We'll soon phase out dairy altogether.