There are plenty of people who get lung cancer who never touched a cigarette. The fact is though that cigarette smoking greatly increases the risk of lung cancer. Yes, there are plenty of women out there who never touched a birth control pill, had a large family and never had an abortion who get breast cancer. Yet the chances of having breast cancer goes down with each child you have. It is not 100% that having kids will absolutely prevent breast cancer, but not having kids increases a woman’s risk.