New research shows kids who come from families under a lot of stress are more likely to get fevers.
The study followed more than 160 kids between the ages of five and 10 for three years.
Researchers say they saw higher rates of illness in children when parents reported bad moods and dysfunctional behavior.
There was one surprising finding.
Researchers found important immune system cells were actually boosted in kids when they were stressed.
Those same cells become weak in stressed out adults.