Found the following on line....

Men have two glands at the base of their penis called Cowper's glands. When some men become erect these glands secrete a drop or two of this slippery clear fluid, known as pre-seminal fluid, at the tip of the penis. Its function seems to be to neutralize the urethra to make the climate more conducive to sperm and therefore make pregnancy more likely. This is because the urethra has to convey both urine and semen at different times and they are opposites in pH level. The pre-seminal fluid appears to neutralize the acid environment in the urethra so that sperm are not killed. (The Cowper's gland fluid may also function as lubrication for intercourse).
Although this fluid is not semen, it can contain live sperm. There have been documented cases of women becoming pregnant even though they did not have intercourse.
http://my.webmd.com/content/article/41/1687_50038.htm

Bulbourethral Glands (Cowper's glands): Pea-sized structures located on the sides of the urethra just below the prostate gland. These glands produce a clear, slippery fluid that empties directly into the urethra. This fluid serves to lubricate the urethra and to neutralize any acidity that may be present due to residual drops of urine in the urethra.
http://my.webmd.com/content/article...0488_6501_00_17

May want to keep this in mind if your having reproductive troubles?? : "function seems to be to neutralize the urethra to make the climate more conducive to sperm and therefore make pregnancy more likely." Best to check with doc.