Cu Boulder Lab R.a.t.s.

Children raised in a rural environment, surrounded by animals and bacteria-laden dust, grow up to have more stress-resilient immune systems and might be at lower risk of mental illness than pet-free city dwellers, according to new research. The study adds to mounting evidence supporting the "hygiene hypothesis," which theorizes that overly sterile environments can breed health problems, says co-author Christopher Lowry, a professor of integrative physiology at CU Boulder.