The seminal fluid that reaches the ejaculatory ducts accounts for approximately twenty per cent of the ejaculate. The seminal vesicles contribute fructose and prostaglandins and account for some sixty per cent of the ejaculate volume. The remainder of the ejaculate is derived from the prostate which contributes spermine, citric acid, zinc, and acid phosphatase. Acquisition of the capacity of sperm to fertilise is poorly understood and may be completed in the female genital tract.
