Declining Male Fertility -- Urban Myth Or Alarming Trend?
July 24, 2000 -- Are sperm count and quality going downhill in modern man? That question has been haunting scientists and prospective parents since 1992, when a Danish study found that sperm count in Western European men has been declining for the last 50 years. Since that time, numerous other studies have come out, some supporting and some debunking the theory -- but all creating fodder for the fertile debate.
"We don't have any evidence that male infertility is increasing," Larry Lipshultz, MD, tells WebMD. "I think what is happening is that more people are going to doctors for infertility because most couples are delaying having kids and they are presenting with problems ... but I don't think we have any reason to think that the incidence is increasing." Lipshultz is a professor of urology at Baylor College of Medicine in Houston.
Concerning study results, Lipshultz says that just as many show that fertility is going down as show that it is not changing or going up. "So there is no final answer [to the question] 'Are sperm counts decreasing?' It is very controversial."
Other fertility and reproductive experts agree. "There are conflicting reports. It is very difficult to obtain information under controlled conditions ... in order to tell precisely that this is happening and to what degree this might be happening," Panayiotis Zavos, PhD, tells WebMD, referring to some of the limitations in collecting data these studies have.
"We continue to see more and more infertility and probably younger people come into our fertility center seeking assistance," he says. "But [is it] an epidemiological trend that the qualitative and quantitative measurements of sperm are deteriorating, or is it because people are coming out of the closet and seeking more assistance?" Zavos, professor of reproductive physiology and andrology at the University of Kentucky in Lexington, is both the director of the Andrology Institute of America and the associate director of the Kentucky Center for Reproductive Medicine and In Vitro Fertilization.
"I am afraid the jury, from a scientific point of view, is still out. There are some data that show that some populations have declining counts, whereas other data are unable to find it," says Kevin Lindsay, PhD, a principal clinical scientist in reproductive biology at Hammersmith Hospital in London. "I am sitting on the fence; I can see evidence both ways. It is something that we need to be aware of and keep an eye on. We need further studies because if decline is real, we may need to be concerned about it."
Some scientists however are not sitting on the fence. In the most recent issue of the International Journal of Andrology,there are no less than four articles on the topic of declining fertility -- two supporting the idea, two refuting it. Many who support the idea of declining sperm count place the blame on environmental factors, including an increase in what is referred to as endocrine disruptors.