Originally Posted by RVCA

"Cum", or seminal fluid, is actually only about 1% sperm and 99% various other fluids. Impressively, in that 1% there is about 400 million spermatozoon, in addition to various secretions from the seminal vesicles (about 70% of the total volume) and the prostate gland (about 30%), plus small contributions from the epididymis and from the bulbourethral glands. Among the constituents of semen are proteins, enzymes, antioxidants, water, and salts, plus the following:
-Sugar fructose, which sperm use as an energy source
-Buffers that keep the pH of semen alkaline between about 7.2 and 7.8
-Viruses such as HIV or Hepatitis B, which may be present at high concentrations in the seminal fluid of infected men

Well, at least, that's what James' mom tells me.