What happens when a mom and dad smoke in the house aroudn kids?

2X or 3X disease. Smoke around babies has been shown to double to triple the rate of ear & respiratory infections and aggravates infantile asthma.Those who smoke in front of kids also teach them it is "cool" to do the type of habit that will destroy their health.
2nd hand smoke. Second hand smoke is not good for the kids. The kids unavoidably inhale second hand smokes and it does damage their lungs, cause sneezing, aggravate asthma, and temper tantrums.