03/07/2011 02:59 pm ET | Updated May 25, 2011

Sperm Meets Chemicals: Are They Really Making Men Infertile?

The connection between chemical exposure and diminished sperm count has been generating real buzz recently, with several new reports lending credence to the idea that environmental factors diminish male fertility. So what's new to the conversation and what does it mean for men?

Last week a report published in the International Journal of Andrology showed a possible link between sperm counts and environmental factors.

The BBC reports that scientists looked at three groups of men born between 1979 and 1987 to compare sperm counts. Those born between 1979 and 1981 had the highest counts, followed by those born between 1982 and 1983. Men born after 1987 had the lowest counts, which, researchers say, is likely tied to environmental factors.

Dr. Allan Pacey, a lecturer in andrology -- the study of male reproductive health -- at the UK's University of Sheffield told the BBC that the study highlights a pressing need for more research identifying specific harmful chemicals and removing them from the environment:

"The best working theory we have to explain why sperm counts may be declining is that chemicals from food or the environment are affecting the development of testicles of boys in the womb or in their early years of life."

Another new study, this one from the journal Environmental Health Perspectives, affirmed that need. Researchers found a link between short anogenital distance (the length between the genitals and anus) and diminished sperm count and quality in male rodents.

For years, scientists have wondered if differences in AGD are caused by chemical exposure. In 2005 the question attracted a lot of attention when Shanna Swan -- a reproductive epidemiologist at the University of Rochester and one of the new study's authors -- published a report linking elevated concentrations of phthalates (plasticizers used in everything from nail polishes to plastic plumbing) to diminished AGD. The findings caused such a stir that, Science reports, the U.S. government subsequently convened 11 scientists to examine its findings.

While the panel deemed Swan's results "inconclusive," it encouraged her to repeat her study with larger samples, which led to Swan's most recent study, and the buzz it continues to raise about chemical exposure and sub-fertility in men.

In an interview with Reuters, Swan said that her most recent study doesn't directly address the potential relationship between phthalate exposure and sperm count, "but it does answer the question of why we should care about AGD." In short, more research is necessary, but scientists remain very interested in a potential link.

In the meantime, agencies like the Environmental Protection Agency are closely monitoring the potential effects of phthalate exposure and male reproduction as well. The EPA writes:

The most sensitive system is the immature male reproductive tract, with phthalate exposure resulting in increased incidence of undescended testes, decreased testes weight, decreased anogenital distance (distance between the anus and the base of the penis), and other effects.