Hi Kmader
Do you smoke, or is your son around others that do smoke ?
He may be a 'passive' smoker, this means that he's subjected to people that smoke around him.
I'll re-post your concern about this in the Blood Disorders Forum .. don't worry about this title, he hasn't got a dosorder, is just that there are people who know more about blood, and any effects to blood in there.
I hope you find the answers you are looking for.
Best wishes
Ginger