When A couple is infertile, often the first question asked is, "What's wrong with her?" "There's a common misperception -- even among healthcare providers -- that infertility is a female problem," says Dr. Thomas Walsh, director of the men's reproductive health program at UC San Francisco School of Medicine.
In fact, male infertility is quite common. At least 20% of infertility cases are due solely to male factors such as low sperm count, and in 40% to 50% of cases, male factors contribute. Many male fertility problems go undiagnosed and untreated, however -- either because attention focuses on their partner or because men are reluctant to get help or unable to find it when they seek it.
Numerous factors influence men's fertility. Some infertile men don't produce adequate amounts of sperm to cause pregnancy. Normally, the precursors to sperm -- germ cells -- mature in the testes under the influence of hormones produced by the pituitary gland. Abnormal or absent germ cells, or disorders that affect the production of pituitary hormones, can impair a man's sperm count.
In some cases, genetic disorders cause low sperm production. Klinefelter's syndrome, which affects between 1 in 500 to 1 in 1,000 men, is among the most common. Men with Klinefelter's carry an extra X chromosome (genetically, they are XXY instead of XY). The condition leads to small testicles with very few germ cells, and most of these men suffer from infertility. Tiny missing pieces of genetic material in the Y sex chromosome can result in poor sperm counts too.
Certain lifestyle behaviors, such as smoking and excessive alcohol and drug use, depress men's sperm counts. For some men, high levels of stress can as well.
Sometimes men are able to make sperm in sufficient quantities but poor sperm quality causes conception difficulties. For fertilization to take place, sperm must be able to reach the egg and then penetrate its outer layer. Sperm that don't move well or are abnormally shaped may be unable to do so. As with low sperm count, causes can be genetic or tied to lifestyle.
Even men who produce healthy sperm in adequate amounts sometimes suffer from infertility. Infections such as chlamydia and gonorrhea can damage the vas deferens (the tube leading from the testes to the urethra, through which the sperm travel), blocking it and preventing sperm from leaving the body.
Some men even produce antibodies against their own sperm; functional when first produced, the sperm are quickly damaged by the immune system.
