We are hearing now that the upsurge in childhood asthma may be a result of children living in too sterile an environment. Indeed, when I was a kid it was not unusual at all to see a toddler playing outside, eating the dirt it was sitting in. Asthma was virtually unheard of. Catching measles was looked forward to as it meant you had passed another milestone in the process of growing up. DDT was routinely sprayed throughout the neighborhood. Did we breathe it? Sure, there was no avoiding it. According to Rachael Carson, by now I should be laying thin-shelled eggs or be dead.
Most of your body operates on a use-it-or-lose-it basis so you exercise to preserve your musculature, lungs or whatever, eat spicy foods to stimulate your digestive system, drink red wine (in moderation) to lengthen your life (no one is sure how this works, but the evidence suggests it so why take chances?)
Women who have children seem to have a reduced risk of reproductive tract cancers as well.
Now make sure that everyone in your family understands the necessity of exercising all the organs in whatever manner. Don't get caught like fellow trying to explain to his wife that the woman he was in bed with was there to mitigate his risk of testicular cancer. While he did avoid the testicular cancer, he was reported to have did of lead poisoning.