all the babies had an equally elevated heart rate. they had caught the mother's stress. >> the baby's heart rate. >> reporter: this toddler even seems uncomfortable with the evaluator who was mean to mom. >> we think she picked up cues from the mother. >> we will be a little cautious. >> reporter: they say being aware of this can help to balance your own emotions. the first step to managing second-hand stress. stress is often hurting our health. stress can increase your chance of stroke, heart attack and depression. >> this is interesting. it scares me as a mom. how can stress impact a child's health? >> it can lead to behavioral problems. homes with stress, whether financial, work life balance, arguing parents can affect a child's health long term. >> what's a parent to do? >> be aware. you can't completely eliminate stress from your life but be aware and if you need to have a conversation have it away from your child and do what you can to eliminate any sort of stress from them. >> all right, nikki, thank you very much. abc's nikki battiste.