Is Male Fertility Declining?

When a couple can't conceive, it's often the woman who is willing to undergo any test necessary to find out the problem. Sometimes men don't wish to get tested because they're in denial. But they should since their role in the creation of a new human is just as important. Also, fertility tests for men tend to be faster and less invasive and it's easier to rule out any problems. Statistically infertility is caused (approximately) 50 percent by the woman and 50 percent by the man. Some medical statistics suggest that as high as 20 percent of infertile couples can't conceive solely because of male infertility. Historically infertility has always been seen as a woman's problem but recent advancements in science show that men also play a significant role in infertility.

More than 2.5 million men in the United Kingdom suffer from infertility or sub-fertile (meaning less fertile than the average man). Approximately two million men have a fertility problem in the United States. The numbers are high leading some researchers to speculate whether or not male fertility is declining.

Male Infertility Defined

A man is considered infertile or sub-fertile if his sperm count is less than 20 million per milliliter. A man is normally considered medically sterile if his sperm count is less than 500,000 per ml. Numbers are figured out through a semen analysis. If the numbers are lower than they should be, then more advanced testing is done to determine the cause.

Many doctors suggest a man should be tested if he smokes excessively, has a hazardous and stressful job, has (or currently has) an STD, has had any traumatic injury to the testicles, or had mumps as a child.

Reports of Declining Male Fertility

The National Review of Medicine reported in 2004 that the British Fertility Society conducted a study that found that men's sperm count had fallen by a third in less than 15 years. In 1989 men on average produced 87 million sperm per milliliter. In 2002 the number had dropped 29 percent to 62 million sperm per milliliter. Similar studies in other European countries had comparable results.

In 1992 The British Medical Journal reported that there would be a decline in male fertility by one percent a year. Three years later a study published in the New England Journal of Medicine reported that sperm counts had dropped by two percent in the last two decades.

Possible Explanations

Scientists don't know for sure why the numbers are dropping, but there are many possible explanations. The insecticide DDT has been blamed even though it hasn't been used in the developed world for decades. So much of it was used and for so often that traces can still be found in some places. A chemical in DDT is comparable to the female hormone estrogen which can lower fertility in a man. Other pesticides are thought to also have the effect.

Overall water pollution has been connected to declining male fertility. The journal Environmental Health Perspectives published a study by the Brunel University that showed chemicals that inhibit the function of testosterone are making their way into UK rivers