Male Infertility Factors

Although in the past infertility was thought of primarily as a "woman's" problem, male factors are just as likely as female factors to cause the inability to have a child.

Male Reproductive System

Unlike women, who produce a certain number of eggs in their lifetimes, men continue to produce sperm throughout their lives. A normal male produces over 100 million sperm daily. The testicles produce both sperm and hormones, such as testosterone. After sperm are produced, they pass through the epididymis, a coiled organ that stores and nourishes sperm as they mature. Mature sperm move through the vas deferens, a tube that connects to the seminal vesicles, and other glands, and finally ejaculates through the penis.

When ejaculation occurs, sperm from the seminal vesicles is combined with fluid from the prostate to form semen. The semen is then expelled from the penis and deposited in the vagina, where the sperm begin their journey. Even with millions of sperm being ejaculated, only a few actually reach the fallopian tubes and the egg.

Sperm Quality

In most cases, male infertility is caused by characteristics in the man's sperm. These include:

The number of (living, mature) sperm present in the semen.
The ability of the sperm to swim (motility). Motility is one of the most important factors in male infertility. Sperm with low motility are unable to reach the egg to achieve fertilization.
The structure or shape of the sperm (morphology). Abnormal sperm may be unable to reach the egg, or penetrate the egg if they do reach it.
Semen viscosity. Failure of the semen to liquefy may interfere with sperm moving through the cervix. Also, infection can cause sperm to clump together, reducing motility, or antibodies in the male or female may cause sperm to adhere to one another.
The total volume of semen. If semen volume is too low, there may not be enough fluid to bring the sperm into the cervix, or to protect the sperm from the harmful environment in the vagina. If semen volume is too high, sperm could be diluted by excess seminal fluid.

Causes of male infertility

Unlike female infertility, the exact cause of male infertility is often impossible to determine. However, there are a number of conditions that can result in abnormal findings in the semen analysis.

Ejaculatory dysfunction. Some men may not be able to produce semen, due to neurological diseases, traumatic injury, or post surgical complications.
Anatomical factors, such as testicle size, men with testicles that didn't descend into the scrotal sac, men with only one testicle, etc.
Scarring from past infection, from diseases such as the mumps, or past injury can disrupt testicular function.
Abnormally large veins (varicoceles) can increase the temperature in the scrotal sac, which can decrease sperm count and motility.
Retrograde ejaculation occurs when semen travels to the bladder instead of the urethra. This occurs when the nerves to the bladder are damaged, in cases of injury, surgery, etc.
Exposure to various toxins, drug use, excess alcohol use, use of anabolic steroids, certain medications, diabetes, thyroid problems, or other endocrine unbalances.
Male factor infertility can also be caused by chromosomal abnormalities. Some men are born with abnormal chromosomal genetics. The gene that determines the production of sperm is located on the Y chromosome, and this gene may be deleted congenitally, leaving the man without any genetic information to produce sperm. Other chromosomal abnormalities have been known to cause infertility, such as Klinefelter’s Syndrome, in which a man is born with 47 chromosomes instead of 46 (extra X chromosome).

Treatment for male infertility includes intrauterine insemination (IUI) in cases of mild male factor infertility, and in vitro fertilization (IVF) with intracytoplasmic sperm injection (ICSI) for severe male factor infertility.

Until recently, male factor infertility was considered untreatable. However, with new procedures such as Intracytoplasmic Sperm Injection (ICSI), sperm washing and others, men with severe infertility can successfully father children.

Additional tests may be recommended to evaluate the quality of sperm, such as Sperm DNA Fragmentation or Sperm Penetration Assay.

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