Most people assume that smoking causes cancer because cigarettes themselves are carcinogenic, but a new study has shown that's not the only way the habit wreaks havoc on the body--the male body, specificially. Smoking seems to make the Y chromosome disappear. Last year, researchers discovered a connection between loss of the Y chromosome and a shorter life span, as well as an increased risk of dying, specifically, from cancer. While these studies affect only males--since they alone carry the Y chromosome--this doesn't mean smoking is any less harmful to women. Sorry, ladies.