Might excessive masturbation in male adults and male teenagers lead to anything bad like making you sterile?

Not physical: Generally, entertaining yourself is a good thing; it keeps you comfortable and lets you focus on regular activities, and you learn about your mind and body to prepare you for adult life. If you're obsessed with erotica, or the unrealistic images that you'll see there, so that you know it's really interfering with your social development / relationships, get with your personal physician; we can hel.

Not: masturbation does NOT cause sterility.