The headline is humorous, but the issue is potentially serious and requires further investigation - especially if it is generally true across populations. The sperm count of French men fell by one-third between 1989 and 2005, according to the results of a study of 26,600 men published on Wednesday in the Human Reproduction magazine.
"To our knowledge, it is the first study concluding a severe and general decrease in sperm concentration and morphology at the scale of a whole country over a substantial period," the study, which was led by the French Institute for Public Health Surveillance, said.
The study used data from tests on the sperm of men aged between 18 and 70 whose partners were undergoing assisted reproductive technology (ART) at 126 centres around France. The women were all infertile, having both fallopian tubes either absent or blocked.
The tests showed a decrease in the men's sperm count of 32.2 per cent over the 17-year period, with the average concentration for a 35-year-old man falling from 73.6 million sperm per millilitre of semen to 49.9 million.
The results also showed a "significant, but not quantifiable" increase in the percentage of sperm with abnormal forms - another indicator of sperm quality.
The study took into account the men's age, but not socioeconomic factors such as smoking and weight, which are known to affect sperm quality.
While the results still put the participants well above the threshold for male fertility of 15 million sperm per millilitre, the authors of the study were nonetheless alarmed by the sharp downward trend.
"This constitutes a serious public health warning," they said.
Researchers have for years debated whether infertility is really on the march, as suggested by some reports.
The French researchers acknowledged the controversy caused by the fact that the studies were conducted on small, biased populations, but said more and more data supported the hypothesis that fetal exposure to endocrine disruptors - chemicals that interfere hormone development - could be impairing reproductive development.
"The link with the environment particularly needs to be determined," they said.