It’s widely known and accepted that neonicotinoid pesticides are killing off the bees. But what are they doing to humans?

Messing with our hormone production, according to a team of researchers in Quebec.

Elyse Caron-Beaudoin, a postdoctoral fellow at the University of Montreal’s School of Public Health, wanted to know if neonics have a long-term effect on human hormone production. Based on her research, Caron-Beaudoin and her team concluded that because some neonics act as hormone disruptors, they can affect unborn babies during pregnancy, and they can also fuel breast cancer.

Caron-Beaudoin and her team couldn’t experiment on actual pregnant women or breast cancer patients, so they did their research using models they constructed in the lab. What they found was that neonics, at concentrations found in the environment, cause increased activity of an enzyme responsible for estrogen production.

In most types of breast cancer, the proliferation of cancerous cells is driven by increased estrogen production. And according to the researchers, pervious studies show fluctuating hormone levels during pregnancy can harm babies.

The full results of the research will appear in an upcoming issue of Environmental Health Perspectives.

Read ‘New Research Finds Bee-Killing Pesticides May Be Impacting Our Health

TAKE ACTION: Tell the U.S. EPA to ban neonicotinoid pesticides