Last saturday when I masturbated, I noticed a small change in colour of my sperm. Most of my sperm was white as it always was, but a small part was a bit yellowish and dirty. When I masturbated just now, half of my sperm was brownish and the other half was white like normally. Any idea how my sperm suddenly can get part brown. I'm kinda freaking out here now being worried and all since this has never happend before. (I'm 23) Anyone else who has had this or any idea what it could be. Otherwise I will have no other option and visit my doctor.