An estimated 10 percent to 15 percent of couples are classified as infertile, which means that they've been trying to get pregnant with frequent, unprotected intercourse for at least a year with no success.
In about half the cases, male infertility is a factor. Causes of male infertility include abnormal sperm production or function, impaired delivery of sperm, general health and lifestyle issues, and exposure to certain environmental factors.
Even if male infertility is a factor, the female partner also may have something going on that interferes with conception. You and your partner may both need treatment to achieve pregnancy. But don't get discouraged. A number of tests and treatment options make it possible to diagnose and overcome most causes of male infertility.
The main sign of male infertility is the inability for couples to get pregnant. There may be no other obvious signs or symptoms of male infertility. However, if male infertility is caused by a hormonal problem, you may have signs and symptoms such as reduced hair growth on your face or body, or a low sex drive.
Male fertility is a complex process that involves many factors, including the release of hormones that trigger the growth of reproductive organs and the production of sperm. To get his partner pregnant, a man must be able to deliver healthy sperm into the vagina that are able to reach, penetrate and fertilize a woman's egg.
- Sperm must be properly shaped and able to move toward the egg for fertilization to occur. If the shape and structure (morphology) of the sperm are abnormal or the movement (motility) is impaired, sperm may not be able to reach or penetrate the egg.
- There has to be enough sperm in the semen to make pregnancy likely. A normal sperm concentration is greater than or equal to 20 million sperm per milliliter of semen. A count of 10 million or fewer sperm per milliliter of semen indicates low sperm concentration (subfertility). Rarely, a man is unable to produce any sperm at all.
Your doctor may use number of tests to try to determine exactly what's causing the problem. In about half the cases of male infertility, an exact cause is never found. But even when the cause isn't entirely clear, treatment may still help. Causes of male fertility include impaired sperm production or function, impaired sperm delivery, lifestyle, and environmental exposure.
Impaired production or function of sperm
A number of specific conditions can cause problems with sperm:
Varicocele. A varicocele is a swollen vein in the scrotum that may prevent normal cooling of the testicle, leading to reduced sperm count and motility.
Undescended testicle. Undescended testicle occurs when one or both testicles fail to descend from the abdomen into the scrotum during fetal development. Because the testicles are exposed to the higher internal body temperature, compared with the temperature in the scrotum, sperm production may be affected.
Testosterone deficiency (male hypogonadism). Infertility can result from disorders of the testicles themselves, or an abnormality affecting the glands in the brain that produce hormones that control the testicles (the hypothalamus or pituitary glands).
Chromosome defects. Inherited disorders of the testes such as Klinefelter's syndrome — in which a male is born with two X chromosomes and one Y chromosome instead of one X and one Y — cause abnormal development of the testicles.
Infections. Infection may temporarily affect how your sperm moves. Sexually transmitted diseases (STDs), such as chlamydia and gonorrhea, are most often associated with male infertility. These infections can cause scarring and block sperm passage. If mumps, a viral infection usually affecting young children, occurs after puberty, inflammation of the testicles can impair sperm production. Inflammation of the prostate (prostatitis), urethra or epididymis also may alter sperm motility.
Hormonal disorders. These conditions, such as congenital GnRH deficiency (Kallmann syndrome), affect the release of hormones needed for sexual development or sperm production.
Impaired delivery of sperm
Problems with the delivery of sperm from the penis into the vagina can result in infertility. Examples of problems that can interfere with sperm delivery include:
- Sexual issues. Often treatable, problems with sexual intercourse or technique may affect fertility. Difficulties with erection of the penis (erectile dysfunction), premature ejaculation, painful intercourse (dyspareunia), or psychological or relationship problems can contribute to infertility.
Blockage of epididymis or vas deferens. Some men are born with blockage of the part of the testicle that stores sperm (epididymis), or have a blockage of the tube that carries sperm (vas deferens) from the testicle out to the penis.
- Retrograde ejaculation. This occurs when semen enters the bladder during orgasm rather than emerging out through the penis. Various conditions can cause retrograde ejaculation, including diabetes, bladder, prostate or urethral surgery, and the use of certain medications.
- No semen (ejaculate). The absence of ejaculate may occur in men with spinal cord injuries or diseases. This fluid carries the sperm from the penis into the vagina.
- Misplaced urinary opening (hypospadias). A birth defect can cause the urinary (urethral) opening to be abnormally located on the underside of the penis. If not surgically corrected, this condition can prevent sperm from reaching the woman's cervix.
- Anti-sperm antibodies. Antibodies that target sperm and weaken or disable them usually occur after surgical blockage of part of the vas deferens for male sterilization (vasectomy). Presence of these antibodies may cause infertility.
- Cystic fibrosis. Men with cystic fibrosis often have a missing or obstructed vas deferens.
General health and lifestyle
A man's general health and lifestyle may affect fertility. Some common causes of infertility related to health and lifestyle include:
- Alcohol and drugs. Alcohol or drug dependency can cause reduced fertility. Anabolic steroids, for example, which are 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.
- Tobacco smoking. Men who smoke may have a lower sperm count than do those who don't smoke. Secondhand smoke also may affect male fertility.
- Emotional stress. Stress may interfere with certain hormones needed to produce sperm. Your sperm count may be affected if you experience excessive or prolonged emotional stress. A problem with fertility itself can sometimes become long term and discouraging, producing more stress. Infertility can affect social relationships and your sex life.
- Other medical conditions. A severe injury, major surgery or cancer can affect male fertility. Certain diseases or conditions, such as kidney disease, cirrhosis, sickle cell anemia and celiac disease can interfere with normal sperm production.
- Age. A gradual decline in fertility is common in men older than 35.
- Malnutrition. Deficiencies in nutrients such as vitamin C, selenium, zinc and folate may contribute to infertility.
- Obesity. Being overweight can cause hormone changes that reduce male fertility.
Overexposure to certain environmental elements such as heat, toxins and chemicals can reduce sperm production or function. Specific causes include:
- Pesticides and other chemicals. Herbicides and insecticides may cause female hormone-like effects in the male body and may be associated with reduced sperm production and testicular cancer. Lead exposure also may cause infertility.
- Overheating the testicles. Frequent use of saunas or hot tubs can temporarily impair your sperm production and lower your sperm count. Sitting for long periods or wearing tight clothing also may increase the temperature in your scrotum and reduce sperm production.
- Exposure to radiation or X-rays. Exposure to radiation can impair sperm production. It can take several years for sperm production to return to normal. With high doses of radiation, sperm production can be permanently impaired.
- Cancer and its treatment. Both radiation and chemotherapy treatment for cancer can impair sperm production. The closer radiation treatment is to the testicles, the higher the risk of infertility.
If you and your partner are unable to become pregnant within a reasonable time, see your doctor. Some infertile couples have more than one cause of their infertility. Your doctor will usually begin a comprehensive infertility examination on both you and your partner.
In some cases, the cause of your infertility may be unclear, or it may take a number of tests to determine the cause. Infertility tests can be expensive and may not be covered by insurance — find out what your medical plan covers ahead of time.
For a man to be fertile, the testicles must produce enough healthy sperm, and the sperm must be ejaculated effectively into the woman's vagina. Tests for male infertility attempt to determine whether any of these processes are impaired.
- General physical examination and medical history. This includes examination of your genitals and questions about illnesses, disabilities and surgeries that could affect fertility. Your doctor will want to know what medications you take and your sexual habits. Your doctor may also ask about your sexual development as a boy and whether you've had any signs of low testosterone, such as decreased body or facial hair.
- Semen analysis. This is the most important test for the male partner. Semen is generally obtained by masturbating or by interrupting intercourse and ejaculating your semen into a clean container. A laboratory analyzes the physical characteristics of your semen, the number of sperm present and looks for any abnormalities in the shape and structure (morphology) and movement (motility) of the sperm. The lab will also check your semen for signs of problems, such as infections or blood. Often sperm counts fluctuate from one specimen to the next, so your doctor may want to evaluate a few different samples. If your sperm analysis is normal, your doctor will likely recommend thorough testing of your female partner before conducting further male infertility tests.
Depending on initial findings, your doctor may recommend additional, more specialized tests that can help identify the cause of your infertility. These can include:
- Scrotal ultrasound. Ultrasound, which uses high-frequency sound waves to produce images of structures within your body, can help your doctor look for evidence of a varicocele or obstruction of the epididymis.
- Hormone testing. Hormones produced by the pituitary and hypothalamus glands and the testicles play a key role in sexual development and sperm production. Your doctor may recommend a blood test to determine the level of testosterone and other male hormones that affect fertility. A number of infertility problems can be caused by an underlying condition that affects hormone levels.
- Genetic tests. These tests are used if your doctor suspects your fertility problems could be caused by an inherited sex chromosome abnormality. When sperm concentration is extremely low, genetic causes could be involved. A blood test can reveal whether there are subtle changes in the Y chromosome.
- Testicular biopsy. This test involves removing samples from the testicle with a needle. It may be used if your semen analysis shows no sperm at all. The results of the testicular biopsy will tell if sperm production is normal. If it is, your problem is likely caused by blockage or another problem with sperm transport.
- Anti-sperm antibody tests. These tests are used to check for immune cells (antibodies) that attack sperm and can affect their ability to function. You are especially likely to have anti-sperm antibodies if you've had vasectomy reversal.
- Vasography. In some cases, contrast dye is injected into each vas deferens to see whether they are blocked.
- Specialized sperm function tests. A number of different tests can be used to evaluate how well your sperm survive after ejaculation, how well they can penetrate the egg membrane, and whether there's any problem attaching to the egg.
Treatment of male infertility depends on the cause, how long you've been infertile, your age, and personal preferences. In all cases of infertility, the female partner also will need to be evaluated and may need treatment. In some cases, treatment of the female partner can compensate for male fertility problems. Your doctor may try to improve your fertility by either correcting an underlying problem (if one is found) or trying treatments that seem like they may be helpful. Sometimes an exact cause for fertility can't be identified. But, even if an exact cause isn't clear, your doctor may be able to recommend treatments that work.
Treatments for male infertility include:
- Surgery. For example, a varicocele can often be surgically corrected, increasing fertility, or an obstructed vas deferens can be repaired.
- Treatments for sexual problems. Treating conditions such as erectile dysfunction or premature ejaculation can improve fertility. Approaches can include medication or counseling.
Hormone issues. In cases where infertility can be caused by too much or too little of certain hormones, or problems with the way the body uses hormones, your doctor may recommend treatment with hormones or medications that change hormone levels.
- Assisted reproductive technology (ART). For blockage of the vas deferens, retrograde ejaculation, or other problems with sperm delivery, sperm can be taken directly from the testicles or recovered from the bladder and injected into an egg. The most effective ART treatment is in vitro fertilization (IVF). This procedure involves surgically removing an egg from a woman's ovaries, combining it with sperm in the lab, and then placing the fertilized egg into the uterus.