Environment Plays Role in Sex of Child

(Ivanhoe Newswire) -- The sex of a child is determined by a man’s sperm. An X chromosome results in a girl, and a Y chromosome brings about a baby boy. But now a new study finds the environment may have an impact on the X and Y chromosomes. It shows environmental pollutants could be changing the ratio of sperm carrying the X or Y chromosomes. Specifically, the research finds there’s a slight increase in the number of sperm bearing the Y chromosome in men exposed to pollutants.

For the study, Swedish researchers looked at the effects of persistent organochlorine pollutants (POPs) among 149 Swedish fishermen. The men fished in the Baltic Sea, which is heavily polluted. The fishermen are affected because they often consume large quantities of local fish.

Researchers found fishermen with a larger amount of two main POPs in their blood had a significant increase in the number of Y chromosomes in their sperm. Researchers also say age, smoking and hormone levels did not change this outcome.

Study authors say they believe this is the first study to show the distribution of sex chromosomes in sperm can be affected by exposure to POPs. However, the study set up did not enable them to determine if the increase in the Y chromosome sperm would lead to more boys being born. They say this study is too small to determine that outcome and a much larger study needs to be done.

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SOURCE: Human Reproduction, published online April 27, 2005