For most men, the only sign of low sperm count men is the inability to conceive a child (infertility). A couple is considered infertile if they're unable to conceive after one year of regular intercourse. If sperm production is impaired by an underlying hormonal problem, you may have other signs such as decreased facial or body hair or problems with sexual function.

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Although in many cases the exact cause isn't always clear, possible reasons for low sperm count include:

• Varicocele. This is a swollen vein inside the scrotum that can affect sperm production. This common cause of male infertility can be repaired with minor surgery.
• Damaged sperm ducts. Inherited conditions, infections, surgeries or injuries can damage the delicate duct system that carries sperm from the testicles into the penis.
• Anti-sperm antibodies. Men who have anti-sperm antibodies have an immune system response that attacks their own sperm. Common in men who have had a vasectomy reversal, this condition can also be caused by other problems such as an injury or infection.
• Problems with sperm production. These issues can be caused by a genetic (inherited) condition such as Klinefelter's syndrome or a hormonal disorder such as a health problem that affects the pituitary gland in your brain. If you have an inherited condition, you're more likely to have complete lack of sperm in your semen (azoospermia).

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Factors that increase your risk of low sperm count include:

• Genetic or hormonal problems. Certain health conditions affect sperm production, such as Klinefelter's syndrome or a problem with hormone production.
• Substance abuse. Sperm count can be reduced by use of illegal drugs such as cocaine or marijuana.
• Smoking. Smoking cigarettes affects sperm production. Secondhand smoke may also lower sperm count.
• Being overweight. Being obese has been shown to cause hormonal changes that affect sperm production.
• Exposure to environmental toxins. Exposure to radiation therapy, certain chemicals, heat and some medications can temporarily reduce sperm production.
• Cancer treatment. Radiation treatment and chemotherapy can hamper sperm production.
• Certain surgeries or injuries. Surgeries or injuries that affect the testicles or glands that produce hormones can affect sperm production.

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If you and your partner are having trouble getting pregnant after a year of regular intercourse, see a doctor.

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When you see a doctor because you're having trouble getting your partner pregnant, your doctor will try to determine the underlying cause. Sperm production is complex and requires normal functioning of the testicles (testes) as well as the hypothalamus and pituitary glands — organs in your brain that produce hormones that trigger sperm production. Problems with any of these systems can affect sperm production.

Initial examination
Expect to answer detailed questions about your medical history and any sexual issues. Your doctor will do a careful physical examination of your reproductive organs to look for signs of a problem such as a varicocele — a varicose vein of the testicle.

Semen analysis
Low sperm counts are diagnosed as part of a semen analysis test. Sperm count is generally determined by examining semen under a microscope to see how many sperm appear within squares on a grid pattern. In some cases, a computer may be used to measure sperm count. If you have no visible sperm in your semen sample, your doctor may use a more involved test to try to isolate any sperm present in your semen for examination.

To collect a semen sample, your doctor will have you masturbate and ejaculate into a special container. It's also possible to collect sperm for examination during intercourse, using a special condom. Because measurements from sample to sample can vary widely, you'll need to present a few samples for your doctor to get a clear picture of the quantity — and health — of your sperm.

Normal sperm densities range from 20 to greater than 100 million sperm per milliliter of semen. While men can reproduce with much lower numbers of sperm, your chance of getting your partner pregnant decreases along with decreasing sperm counts:

• Less than half the men with sperm counts between 12.5 and 25 million sperm per milliliter are able to get their partner pregnant.
• Less than one-quarter of men with sperm counts less than 12.5 million sperm per milliliter are able to get their partner pregnant.

There are many factors involved in reproduction, and some men with low sperm counts have fathered children. Likewise, some men with normal sperm counts have been unable to father children. The number of sperm in your semen is only one factor. Even if you have enough sperm, you're much more likely to achieve pregnancy if at least half of your sperm have a normal shape and show normal forward movement (motility).

Your doctor may conduct further tests if he or she suspects your low sperm count is caused by an underlying condition. Your doctor will also want to make sure your female partner has been tested for any fertility problems.

Ultrasound
If your doctor suspects your reproductive tract is blocked, he or she may order an ultrasound test. Scrotal ultrasound is used to detect a varicocele or blocked epididymis. 

Testicular biopsy
This procedure uses a fine needle to take a small tissue sample of the testicle to look for any abnormalities and to determine if sperm are present. The doctor will numb the area where the samples will be taken (generally one from either testicle). The procedure isn't painful, but you may feel sore for a few weeks afterward.

Blood tests and genetic tests
If your doctor suspects your low sperm count may be caused by an underlying hormonal condition, your doctor may test your blood for hormone levels. In some cases, problems with sperm production are linked to a genetic (chromosomal) abnormality. If your doctor suspects this is the case, genetic testing can be used to check for absent or abnormal regions of the male chromosomes (Y chromosomes).

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Low sperm count can cause male infertility.

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Treatment for low sperm count depends on the cause. Your doctor will carefully test you, but sometimes an exact cause is never found. Even when this is the case, your doctor may still be able to recommend a treatment that will help you and your partner achieve pregnancy. Your doctor will also want to make sure your female partner has been evaluated. Treatments to boost female fertility can help compensate for low sperm count — and increase your chance of pregnancy.

Treatments for low sperm count include:

• Varicocele repair. Varicoceles are a common cause of male infertility. A swollen vein in the scrotum, a varicocele can cause reduced sperm count and abnormally shaped sperm. Surgical treatment to repair a varicocele can improve the sperm count and increase the chances for a pregnancy.
• Hormone replacement. If the hypothalamus or pituitary glands in your brain aren't producing normal hormone levels, your doctor may recommend hormone treatment (gonadotropin injections). In some cases, it can take up to a year of regular injections to achieve normal fertility.
• Treating infections. If a blood test reveals high numbers of white blood cells, you may have an infection of the reproductive tract that affects sperm production. Antibiotic treatment may cure the infection, but may not restore fertility.

Assistive reproductive techniques. Also called ARTs, these procedures are an effective treatment for men with a low sperm count, because only a small number of sperm are needed. ARTs include:

• In vitro fertilization (IVF). During IVF, the female partner receives daily hormone injections for five to 12 days to stimulate egg production in the ovaries. When the eggs are mature, they're removed from the ovaries and combined with sperm in the laboratory. Fertilized eggs are placed into the woman's uterus.
• Intracytoplasmic sperm injection (ICSI). Used along with IVF, this procedure is used to inject a single sperm from the male partner into the female egg.

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A number of factors can help you maintain higher numbers of healthy sperm — and increase your chances of conceiving a child. Here are a few lifestyle decisions that may help:

• Don't smoke. Smoking can damage sperm and interfere with sperm production and libido. Secondhand smoke also may cause low sperm count.
• Avoid excessive drinking. Excessive alcohol consumption (more than two drinks a day for men) has been shown to reduce sperm production and affect libido.
• Steer clear of illegal drugs. Drugs including anabolic steroids, marijuana and cocaine can all affect sperm production and libido.
• Keep the weight off. Obesity is linked to decreased sperm production.
• Don't get a vasectomy. If there's any possibility you may want to father a child in the future, use other methods of birth control. Even though vasectomies can sometimes be reversed, you may have a reduced sperm count.
• Keep cool. Avoid hot tubs, saunas and other sources of sustained heat, which can temporarily reduce sperm count. Tight underwear and sitting for long periods or using a laptop computer also may increase scrotal temperature.

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Taking care of yourself can help increase the number of healthy sperm in your semen.

• Frequency of ejaculation. It's important to have sex on a regular basis around the time of ovulation, when your partner can get pregnant. But ejaculating more than a few times a week can reduce the number of sperm present in your semen.
• Avoid the heat. High body temperatures have been shown to decrease sperm production. Avoid hot tubs, saunas and exposure to hot weather. Tight fitting shorts or prolonged laptop computer use also may increase the temperature of your testicles, decreasing sperm production.
• Make healthy lifestyle choices. Staying at a healthy weight and avoiding tobacco, excessive drinking and illegal drugs can all help reduce the risk of low sperm count.

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