There are multiple possible negative side effects that steroids can have on men. Most commonly known side effects that are not myths are the decrease in the size of the male testes, possible male gynecomastia (fatty tissues around the pectoralis muscles) and baldness.
There are also possble issues with cardiovascular functioning in later years, these are however not restricted only to men.
Bat will eat mosquitoes and other bugs which may carry bad diseases or bacteria (If your talking about Bats the species around kids?)
"Because they still aren't good for your Health." (Tobacco is and always will be a drug).