Did a little research:
Here's a listing of some of semen's ingredients:
Sugars: Fructose, sorbitol, inositol
Proteins and amino acids: glutathione, deoxyribonucleic acid (DNA), creatine
Minerals: Phosphorus, zinc, magnesium, calcium, potassium
Vitamins: Ascorbic acid (vitamin C), vitamin B12, choline
Hormones:
Testosterone, prostaglandins
Body byproducts: Lactic acid, urea, uric acid, nitrogen
Test aye?
http://www.dontspitswallow.com/cum_nutrition.shtml