Causes of Male Infertility

In This Article:
Causes of Infertility
Causes of Female Infertility
Causes of Male Infertility

Not surprisingly, sperm disorders account for the most common factors affecting infertile men, and are often symptomatic of other diseases or disorders.   To that end, a semen analysis is often critical in determining a man’s fertility.  The analysis looks at eight factors, including:

Semen volume: Normal volume is 1.0-6.5 milliliters (mL) per ejaculate.  In very rare cases, there is an absence of semen, termed aspermia.

Sperm count: Normal sperm count is defined by the World Health Organization as having over 20 million sperm per mL.  A count of under 20 million/mL is termed oligospermia while the absence of sperm altogether is termed azoospermia (see expanded entries for both below).

Sperm motility: Forward motion capacity.  Normal motility is about 8 million sperm per mL showing good motility.

Sperm morphology: Measuring how many sperm are shaped normally, in which 70% indicates good morphology.  Abnormally shaped sperm appear variously at the head (two heads, tiny heads, round heads) and tail (two tails, short tails).  These shapes tend to affect their motility as well.

Other factors include liquefaction time, pH levels, and fructose levels.   An off-average number in any factor can signify infertility.


Azoospermia is a condition in which a semen analysis shows an absence of sperm in a man’s semen, although azoospermia is sometimes diagnosed even if as many as 500,000 sperm are found.

All told, this may be a testicular problem, where the testes simply aren’t producing any.  It’s also possible that the testes are producing sperm, but they aren’t being delivered.  In this case, the problem is in either the ductal system carrying the sperm, or in the process known as emission, in which sperm moves to the urethra prior to ejaculation.


Defined as having a sperm count of under 20 million spermatozoa per milliliter, in short what this means is that there is an insufficient amount of sperm in the semen to make fertility likely.  However, oligospermia does not automatically indicate infertility.