Causes of infertility in men
Up to 15 percent of couples are infertile. In up to half of these couples, male infertility plays a role.
Male infertility is due to low sperm production, abnormal sperm function or blockages that prevent the delivery of sperm. Illnesses, injuries, chronic health problems, lifestyle choices and other factors can play a role in causing male infertility. Male fertility is a complex process. To get your partner pregnant, the following must occur:
You must produce healthy sperm.
Initially, this involves the growth and formation of the male reproductive organs during puberty. At least one of your testicles must be functioning correctly, and your body must produce testosterone and other hormones to trigger and maintain sperm production.
Sperm have to be carried into the semen.
Once sperm are produced in the testicles, delicate tubes transport them until they mix with semen and are ejaculated out of the penis.
There needs to be enough sperm in the semen.
If the number of sperm in your semen (sperm count) is low, it decreases the odds that one of your sperm will fertilize your partner’s egg. A low sperm count is fewer than 15 million sperm per milliliter of semen or fewer than 39 million per ejaculate.
Sperm must be functional and able to move.
If the movement (motility) or function of your sperm is abnormal, the sperm may not be able to reach or penetrate your partner’s egg.
Overexposure to certain environmental elements such as heat, toxins and chemicals can reduce sperm production or sperm function. Specific causes include:
- Industrial chemicals. Extended exposure to benzenes, toluene, xylene, pesticides, herbicides, organic solvents, painting materials and lead may contribute to low sperm counts.
- Heavy metal exposure. Exposure to lead or other heavy metals also may cause infertility.
- Radiation or X-rays. Exposure to radiation can reduce sperm production, though it will often eventually return to normal. With high doses of radiation, sperm production can be permanently reduced.
- Overheating the testicles. Elevated temperatures impair sperm production and function. frequent use of saunas or hot tubs may temporarily impair your sperm count.
Sitting for long periods, wearing tight clothing or working on a laptop computer for long stretches of time also may increase the temperature in your scrotum and may slightly reduce sperm production.
Health, lifestyle and other causes
Some other causes of male infertility include:
- Illicit drug use. Anabolic steroids taken to stimulate muscle strength and growth can cause the testicles to shrink and sperm production to decrease. Use of cocaine or marijuana may temporarily reduce the number and quality of your sperm as well.
- Alcohol use. Drinking alcohol can lower testosterone levels, cause erectile dysfunction and decrease sperm production. Liver disease caused by excessive drinking also may lead to fertility problems.
- Men who smoke may have a lower sperm count than do those who don’t smoke.
- Stress can interfere with certain hormones needed to produce sperm. Severe or prolonged stress, including problems with fertility, can affect your sperm count.
- Obesity can impair fertility in several ways, including directly impacting sperm themselves as well as by causing hormone changes that reduce male fertility.
Certain occupations including welding or those involving prolonged sitting, such as truck driving, may be associated with a risk of infertility.