Research by the University of Geneva (UNIGE) found that only 38% of the men it studied in Switzerland had sperm above the standard the World Health Organisation (WHO) considers men to be fertile.
The study, which analyzed sperm from 2,523 men between the ages of 18 and 22 who were conceived and born in Switzerland, found problems with the number and health of sperm in most of the samples.
The Swiss study determined sperm quality by looking at concentration, mobility and morphology (shape).
Multiple studies across the world have revealed a decline in sperm concentration from 99 to 47 million per millilitre over the last 50 years. Below 40 million per millilitre the time required for conception goes up significantly, according to Serge Nef a professor of genetic medicine at UNIGE.
Sperm quality varies significantly from one country to the next with a range of 41 to 67 million per millilitre across Europe. At 47 million per millilitre, Switzerland is near the bottom with Denmark, Norway and Germany.
What might be causing the damage?
The study found a link between smoking during pregnancy and low sperm count. Among those with fewer than 15 million per millilitre 18% had mothers that had smoked during pregnancy compared to only 11% of those with concentrations above 40 million per millilitre.
In addition, researchers found a correlation between poor sperm quality and testicular cancer. Over the last 35 years the rate of testicular cancer has risen in Switzerland to 10 per 100,000, a very high level when compared to other european nations, according to the study. This is probably due to changes in testicular development at the foetal stage, said the report.
Various studies around the world have implicated diet, tobacco, alcohol, air pollution, stress, pesticides, compounds in plastics, and even wearing briefs instead of boxers in the decline of male fertility.
In Switzerland, the number of infertile couples resorting to medically assisted procreation doubled in the eight years from 2002 reaching around 6,000 in 2010.