Kids' Bones Growing Brittle

Kids today break their arms more often than children did 40 years ago, and experts say it's because their bones are getting weaker, AP reports. A lack of milk, sunshine and exercise means many children aren't building adequate bone mass, and in extreme cases are developing bone-softening rickets, the scourge of the 19th century.

Changing lifestyles and the rise in childhood obesity are reducing bone mass during the years that will make all the difference later in life when adults can develop the fragile bones of osteoporosis. Almost half of peak bone mass develops when children are teens. "This potentially is a time-bomb," warned a health expert. (More bones stories.)