New research is out suggesting some unsanitary habits many kids have may not be so unhealthy after all.

According to the Journal Pediatrics, children who bite their nails and suck their thumbs are about one-third less likely to develop certain allergies.

Researchers say the findings may be another example of what’s called the hygiene hypothesis, the idea that being too clean may increase a child’s risk of allergies.

According to Prof. Malcolm Sears, Mcmaster University School of Medicine, “early exposure to dirt is not a bad thing. When they suck their thumbs or bite their nails they’re exposing themselves to addition microbes or dirt which is stimulating the immune system.”

Researches say this isn’t a recommendation for kids to take up nail-biting and thumb-sucking, they said “just let kids be kids.”