Have you been tested for STD's recently? If so and everything came back okay, I would say it may just be normal for you. Next time you are at the doctor, you could ask these same questions and see what they say.
I have to say i don't know that I have ever really paid much attention to the color of my husband's semen, but I know sometimes the consistency of it can vary. I take the first comment back, his isn't completely colorless or white, there may be a color to it.
Andi
Yellowish semen color can be caused by a simple urinary tract infection. If the infection has spread, it can cause epididymitis or prostatitis.