Conceive in The Summer, Get a Dumb Kid; or, Why My Job Is Alarming

You'd be forgiven for thinking a news story about how the season a child was conceived is linked to intelligence is a bunch of crump, as JW so memorably called the ethanol study I linked to. But that would only be because you couldn't possibly guess the scientific reason it's probably accurate: pesticide spraying.

When researchers linked standardized test scores of 1,667,391 Indiana students in grades 3 through 10 with the month in which each student had been conceived, they found that children conceived May through August scored significantly lower on math and language tests than children conceived during other months of the year.

The correlation between test scores and conception season held regardless of race, gender, and grade level.

Why might this be? According to Dr. Paul Winchester of Indiana University School of Medicine who led the study, says the evidence points to environmental pesticides, used most often in the summer months, as a possible player.

The lower test scores correlated with higher levels of pesticides and nitrates in the surface water (nearby streams and other bodies of water) during that same time period, he told Reuters Health.