Semen quality

Semen quality is a measure of the ability of semen to accomplish fertilization. Thus, it is a measure of fertility in a man. It is the sperm in the semen that are of importance, and therefore semen quality involves both sperm quantity and quality. Decreased semen quality is a major factor of male infertility.

Cryptorchidism, Hypospadias, Testicular cancer and poor Semen quality make up the syndrome known as Testicular dysgenesis syndrome.

There has been evidence for a general decline in sperm counts in Europe and the USA between 1938 and 1990. While these dates were critiqued, further analysis supported the findings. The reason(s) for the decline are unknown.

A semen analysis typically measures the number of sperm per millilitre of ejaculate, and analyzes the morphology (shape) and motility (ability to swim forward) of the sperm (the typical ejaculate of a healthy, physically mature young adult male of reproductive age with no fertility-related problems usually contains 300–500 million spermatozoa, though only a couple of hundred survive in the acidic environment of the vagina to be candidates for successful fertilization). Also usually measured are the concentration of white blood cells, the level of fructose in the semen, and the volume, pH, and liquefaction time of the ejaculate.

A number of factors may influence the accuracy of semen analysis results, and results for a single man may have a large amount of natural variation over time. For this reason, a subfertile result must be confirmed with at least two further analyses.

A man's sperm are mixed with hamster eggs that have had the zona pellucida (outer membranes) removed, and the number of sperm penetrations per egg is measured. No strong correlation has been found between hamster egg penetration rates and the various semen parameters and the role of the hamster egg penetration test in the investigation of the causes of infertility should be evaluated further. However, a negative result on the hamster test correlates with a lower probability of the man's partner becoming pregnant.

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