Causes for Male Infertility

More than 90% of male infertility cases are due to low sperm counts, poor sperm quality, or both. The remaining cases of male infertility can be caused by a range of conditions including anatomical problems, hormonal imbalances, and genetic defects. Sperm abnormalities are a critical factor in male infertility.

What causes male infertility?

Male infertility is usually caused by problems that affect either sperm production or sperm transport. Through medical testing, the doctor may be able to find the cause of the problem.

About two-thirds of infertile men have a problem with making sperm in the testes. Either low numbers of sperm are made and/or the sperm that are made do not work properly.

Sperm transport problems are found in about one in every five infertile men, including men who have had a vasectomy but now wish to have more children. Blockages (often referred to as obstructions) in the tubes leading sperm away from the testes to the penis can cause a complete lack of sperm in the ejaculated semen.

Other less common causes of infertility include: sexual problems that affect whether semen is able to enter the woman’s vagina for fertilisation to take place (one in 100 infertile couples); low levels of hormones made in the pituitary gland that act on the testes (one in 100 infertile men); and sperm antibodies (found in one in 16 infertile men). In most men sperm antibodies will not affect the chance of a pregnancy but in some men sperm antibodies reduce fertility.

How common is male infertility?

Infertility is a widespread problem. For about one in five infertile couples the problem lies solely in the male partner.

It is estimated that one in 20 men has some kind of fertility problem with low numbers of sperm in his ejaculate. However, only about one in every 100 men has no sperm in his ejaculate.

What are the symptoms of male infertility?

In most cases, there are no obvious signs of infertility. Intercourse, erections and ejaculation will usually happen without difficulty. The quantity and appearance of the ejaculated semen generally appears normal to the naked eye. Medical tests are needed to find out if a man is infertile.