Here's a decent WebMD article that discusses the different things they look for in a semen analysis and why, along with a quote:
link
More detailed info on this stuff is on page two of the linked article.
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- Volume. This is a measure of how much semen is present in one ejaculation.
- Liquefaction time. Semen is a thick gel at the time of ejaculation and normally becomes liquid within 20 minutes after ejaculation. Liquefaction time is a measure of the time it takes for the semen to liquefy.
- Sperm count. This is a count of the number of sperm present per milliliter (mL) of semen in one ejaculation.
- Sperm morphology. This is a measure of the percentage of sperm that have a normal shape.
- Sperm motility. This is a measure of the percentage of sperm that can move forward normally. The number of sperm that show normal forward movement in a certain amount of semen can also be measured (motile density).
- pH. This is a measure of the acidity (low pH) or alkalinity (high pH) of the semen.
- White blood cell count. White blood cells are not normally present in semen.
- Fructose level. This is a measure of the amount of a sugar called fructose in the semen. The fructose provides energy for the sperm....