There's no problem. Respect ur body. Masturbation is normal for any adolescent male. Only problem is when u start feeling guilty about it. When out of control it can impact ur life significantly not physically but mentally. How much time do you waste on it.. Think about it. You have so much to do in the day. School studies...friends. If u are doing this excessively you are losing the social touch. That affects ur mind and physically weakness follows. Restrict it. Moderate it. Enjoy it. Don't feel guilty but don't overdo. "You will not loose sperms" "sperms quality doesn't get affected by it" "there's no stock of sperms in the Body" Sperms are produced till very old age also.so don't think about these things. Unnecessary thoughts make your body weak...Not masturbation.