Is it healthy for a 15 yr old to watch ?

I heard on G4.com that german scientists found out that looking at large for ten minutes is healthy. I know that it isnt healthy to watch because kids will get a wrong idea of women, but isnt it healthy to masturbate? I heard if u dont, then the semen in your body will cause an infection because it wont come out. Do 15 year old have semen? (its all clear right, cuz i heard that stuff, pre-ejac was like a lubricant for your sperm to travel through) Do 15 yr olds produce sperm when they masturbate?