Lots of recent research on neonicotinoid pesticides has focused on their deadly effects on honeybees and hives, but few have studied their possible effects on human health.

Now, a Quebec research team has made some disturbing findings, including how the pest killers might affect unborn babies during pregnancy, and how they play a role in fuelling breast cancer.

Elyse Caron-Beaudoin, a postdoctoral fellow at the University of Montreal’s School of Public Health, says while neonic pesticides have passed tests related to their toxicity in order to be approved for use in Canada, no one has looked at the long-term effects of these chemicals on human hormone production.

“And so that’s what we decided to investigate,” Caron-Beaudoin told CTV News Channel from Montreal Thursday.

She and her team decided to focus on estrogen production in two contexts: during pregnancy and during the development of breast cancer.