If you or someone you know has diabetes, is male, and is thinking about becoming a father, it’s time to talk to a doctor about their diabetes medication. Metformin, a drug used to manage type 2 diabetes, may have serious side effects on any children a man might father.

A study from Stanford University and the University of Southern Denmark found a link between Metformin use and genital birth defects in baby boys. Men who took Metformin up to three months before conception had a 5.2% chance of having a baby with birth defects, compared to 3.3% in men who didn’t take the drug.

The study focused on men under 40 with partners under 35 and did not include mothers who took Metformin. Researchers examined birth registries from 1997 to 2016, considering men who filled a Metformin prescription within three months of conception.

Men using Metformin are advised to consult their doctor, especially if they are planning to have children. The study also highlights that diabetes control can affect sperm quality, meaning changing medications could impact conception chances.

Does it surprise you that diabetes medication might affect a father’s child? Do you know anyone on Metformin?