Toddlers Leaking Semen ?

I hope people dont laugh at this but well I am not sure and advice before I go running to the doc would be appreciated (!) - I am attempting to potty train my 3 1/2 year old son (not an easy task !) and whilst he was sitting on the potty out shot cloudy cream like fluid into his pot, and that was it so I put him back in his pants and he then promptly wet himself (typical eh !) . but looking at what was in his pot it looked like semen but I dont know if its possible for boys of this age to have this leakage yet, can anyone advise, would really appreciate it. Thank you