Doctors are finding out that there is a growing incidence of kidney stones in children which can be linked to the modern diet and lifestyle. They are saying that one of the reasons are high levels of oxalates (found in strawberries, blueberries, raspberries, chocolate, peanut butter and nuts) in children, and are urging that children drink more water. The more dehydrated one becomes, the more concentrated the urine becomes, which forms crystals and crystals form into kidney stones. For more information see this article.