Machka 

So do Canadians and Australians.

I grew up on a tall glass of milk a day until I was about 17. Then I quit doing that when I determined it was causing my digestive upset.

I can handle yogurt, hard cheeses, and some ice cream.

Evidently it is genetic. People with a northern European background rarely develop lactose intolerance. But those of us with a southern European background, and other parts of the world, do.