A Michigan State University study indicating that men with higher levels of PCBs in their bodies are more likely to father boys than girls is more evidence of the effects environmental contaminants can have on the human body.
The study, using data from three separate studies in which PCB levels were measured in the bodies of men who ate fish taken from Lake Michigan, found that of the 208 children born to those men, more than 57 percent were boys.
The paper was published in the recent issue of the Journal of Occupational and Environmental Medicine.
"We do not wish to say that having a baby boy is bad, it's just that there were more of them," said Wilfried Karmaus, MSU associate professor of epidemiology, who directed the study. "A change in the proportion of boys to girls, however, indicates that environmental contaminants may play a role in human reproduction."
PCBs are among a number of environmental contaminants that have plagued the Great Lakes for years. They can come from any number of sources, including hydraulic fluids and oils, electrical capacitors and transformers, and a by-product of paper mills that dot the shoreline.
Among the potential dangers of PCBs: disruption of the body's endocrine system and a possible carcinogen.
In this study, Karmaus and colleagues restricted their research to children born after 1963 and to families in which PCB levels were detectable in both fathers and mothers. This was a total of 208 children from 101 families.
They found that men with PCB concentrations of at least 8.1 micrograms per liter of blood were more likely to father boys.
"However," Karmaus said, "we did not detect that the PCB levels of mothers affected the number of boys or girls."
Also participating in the study was Suiying Huang, a former graduate student in MSU's Department of Epidemiology, and Lorraine Cameron of the Michigan Department of Community Health.
The research was funded by a grant from the Agency for Toxic Substances and Disease Registry.
Materials provided by Michigan State University. Note: Content may be edited for style and length.
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