Masturbation has nothing to do with preferred sexuality. It's what you masturbate to, what turns you on. Sometimes somebody may masturbate for the feeling alone, not even to an idea of a specific sex.
As a homo, I can tell you that you don't turn homo. You either are or you aren't. I've never desired women, have always desired men. So, I'm a homo.
I wonder if you're asking this because you like to watch yourself. If so, that has nothing to do with sexuality either. Straight guys like to see themselves get off too. If you're asking for another reason, then it's obvious you need other questions answered.