I've never been a milk drinker. The lactose has given me trouble since I was a baby. Humans really aren't designed to drink cow milk.

Don't get me wrong. IMO there are lots worse things we need to be worried about. The antibiotics and hormones in our meats. High-fat/low-fiber diets. Bacterial contimaination. Ambient radiation. UVA and UVB exposure/skin cancer. Rising levels of diabetes and declining levels of exercise. The obesity epidemic.

It's worth mentioning here that Dr. Joseph Mercola, the owner of the Web site linked in Sam's initial post above, is himself considered on the medical fringe. He's an osteopath, and, among other things, he's well known for an opposition to vaccinations. He's really much more of an entrepreneur than anything else.
Joseph Mercola - Wikipedia, the free encyclopedia

By the way, Dr. Frank Oski, the physician who wrote Don't Drink Your Milk, is the former director of pediatrics at Johns-Hopkins University Medical School; he was never the chief of the medical school or the university hospital itself.