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Professor questions findings of sperm studies

Andrew Ikeman | Fulcrum Staff

Illustration by Kelsey Shore

The long-held theory that the quality and quantity of sperm produced by the average male is decreasing may not be as accurate as once thought. The methodology of the studies—that looked into the quality of the sperm—has been called into question by University of Ottawa researcher Raywat Deonandan, who says the studies only looked at sperm in developed nations, leaving much sperm unexamined and a gap in the argument.

“[The scientific] community has been extensively collecting data … on semen quality,” said Deonandan. “The ways in which sperm quality is assessed is by several things: first is the amount of semen you produce, secondly is the amount of sperm in the semen—therefore, the density, third is the movement of the sperm, and last is what is called morphology, or the shape of the sperm.”

Deonandan points to a study done in the 1990s by Elisabeth Carlsen, that reported the quality of semen around the world was decreasing as being the instigator for the current belief. The data from Carlsen’s, and the subsequent studies, was collected from sperm banks, which gather the data with each donation. Deonandan, however, saw holes in this logic.

“What we decided to do—my student and I—was to investigate the methodologies used to select the data,” said Deonandan. “What we found … was that there is a bias in the way the data was selected. That bias tends to be in the countries it was chosen from. So generally sperm banks tend to exist in wealthy, developed countries … and those countries tend to be very different from countries that are less developed.”

Deonandan also said that lifestyle and environmental factors in developed countries could likely be the cause of the decrease in sperm quality. He also noted the increased use of soy—a pseudo-estrogen—and other things that decay into estrogenic material. While Deonandan’s study is not a definitive answer to why—or even if—the sperm quality is decreasing, he recommends further research.

“What we propose is that someone needs to go and investigate men living in truly non-industrialized parts of the world,” said Deonandan. “If we don’t see the same trends there, then that supports the idea that the modern western lifestyle is contributing to [the decrease in semen quality].”