Flour mill workers have fewer sons

A new study suggests that men who work in flour mills tend to father fewer sons than average - adding to evidence that certain toxic exposures may affect men's reproductive function or the survival of male foetuses.

Using data from the Washington State health department, researchers found that the children of men who worked in flour mills were disproportionately female. Of 59 children born to these workers between 1980 and 2002, 37 - or roughly 63 percent - were girls.

In contrast, just over 51 percent of children born in Washington during that period were boys, according to the findings published in the American Journal of Industrial Medicine.

While the reason for the discrepancy is not certain, on-the-job exposure to chemicals may be involved, according to Dr. Samuel Milham and Eric M. Ossiander, the health department researchers who conducted the study.

Flour mill workers are exposed to a range of pesticides used to keep insects out of stored grains and flour. One pesticide, known as DBCP, has been banned because of its effects on men's fertility and on male births, Milham and Ossiander point out.

The current findings suggest that some pesticides used in flour mills may have similar effects, the researchers speculate.

Mother Nature has always given a slight advantage to males in the male-to-female birth ratio, as death rates among young males are higher. Traditionally, it's been expected that for every 100 girls born, there will be about 105 boys.

However, recent research suggests that this gap is narrowing. One study found that, across the US and Japan, male births have been declining since 1970. In the US, the proportion of males births dipped from 105,5 per 100 female births in 1970, to 104,6 in 2001.

Those researchers speculated that environmental toxins - whether pesticides, heavy metals, solvents or other pollutants - may partially explain this trend. Men's exposure to these chemicals may, for example, specifically damage sperm carrying the Y chromosome, and this could lead to fewer male foetuses.

Male foetuses themselves may also be more vulnerable to such toxins.

The current study found that, besides the low prevalence of male births, boys born to flour mill workers also weighed significantly less than average.

According to Milham and Ossiander, this finding is "unprecedented," and could reflect another toxic effect of the fathers' chemical exposures.



Source : Babynet