What is semen made of?

  Normal semen consists of testicular fluid, epididymal fluid, urethral bulb gland fluid, paraurethral gland fluid, prostate fluid, and seminal vesicle fluid.  These glandular fluids are expelled in a certain order during ejaculation. Before most of the semen is ejaculated, a small amount of fluid is secreted by the urethral bulbous and paraurethral glands. This is followed by a low-viscosity cream-colored fluid consisting of prostatic fluid and a small amount of sperm. The main part of the semen is a high-density sperm portion consisting of testicular, epididymal, vas deferens and some prostatic seminal vesicle fluid. The final part of the seminal fluid is composed of seminal vesicle fluid.