Eat dirt, get worms, be healthy

That's the conclusion from students of "the hygiene hypothesis," currently being tested by scientists as an explanation for the increase in autoimmune disorders (e.g. allergies) in Western countries. 

One leading researcher, Dr. Joel V. Weinstock, the director of gastroenterology and hepatology at Tufts Medical Center in Boston, said in an interview that the immune system at birth “is like an unprogrammed computer. It needs instruction.”
...“Children raised in an ultraclean environment,” he added, “are not being exposed to organisms that help them develop appropriate immune regulatory circuits.”

Do wash hands after using the restroom or handling dirty diapers, the scientists say, but that old mantra to "wash up before dinner"? 

Maybe not.