A latest study shows that its not just a man's sperm but environmental factors that could have an impact on the sex of a child . The study 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.
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 were found to be affected because of their consumption of large quantities of local fish. 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 , however researchers say age, smoking and hormone levels did not change the outcome.
Being the first study of its kind to show that the distribution of sex chromosomes in sperm can be affected by exposure to POPs ,researchers say 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. Thus researchers say that much larger studies need to be done in this regard.