Children who have at least one parent who smokes have 5.5 times higher levels of cotinine, a byproduct of nicotine, in their urine, according to a University of Leicester led study published online.
Having a mother that smokes was found to have the biggest independent effect on cotinine in the urine – quadrupling it. Having a smoking father doubled the amount of cotinine, one of chemicals produced when the body breaks down nicotine from inhaled smoke to get rid of it.