Do you feel guilty for sending your kids off to a crowded and always-messy day care center, rather than hiring a nanny to watch them in your sparkling clean home?

Don't: New research shows that kids who spend their days in the company of other children are 30% less likely to develop leukemia.

The study, from the University of California at Berkeley, analyzed data on 14 studies involving over 6,000 children with leukemia and 13,704 healthy children to measure a correlation between whether the child attended day care or a play group at a young age, and whether he developed leukemia. Most of the studies revealed that a child who'd spent time in day care was 30% less likely to develop the disease; in some cases, the reduction went as high as 40%. "That's a fairly substantial impact on leukemia risk," the study's author, Patricia Buffler, told The National Post. No kidding.

Buffler and her colleagues chalk the dramatic downturn in leukemia to "the hygiene hypothesis," which theorizes that children who are exposed to germs and viruses from an early age gain stronger immune systems later in life, and are able to fight off serious illness more easily than children who'd been more sheltered.

"Some parents think: 'Well, I'll keep my child out of daycare and he won't get all these childhood infections and I won't miss days of work,'" said Buffler. "But the children who are isolated seem to be at greater risk of [developing] leukemia later in life."

So take note and don't be too concerned if your kid comes home from his preschool class with the sniffles. For all you know, his cold might be just the trick for keeping childhood cancer away.