I'm 42 years old and I recently had this unpleasant experience: brownish disgusting semen everytime I ejaculated.
I freaked out and I immediately consulted a urologist who told me that it was perfectly normal and nothing to worry about. He didn't even prescribe any medication.
Here's what I did: lots of masturbation to get rif of that crap. And it worked!

I haven't had any sexual experience (incl. masturbation) in a long time, sex is not that important to me anymore. Could that be the explanation for the brown/red semen?