Cohort Study: Preconception paternal use of metformin linked to increased risk of congenital problems in offspring.

Preconception Antidiabetic Drugs in Men and Birth Defects in Offspring: A Nationwide Cohort Study – Annals of Internal Medicine (link to abstract – $ for full-text)

Commentaries:

Paternal metformin use associated with major birth defects if used during period of sperm development – American College of Physicians

Expert reaction to study of birth defects and diabetic men using metformin during sperm development – Science Media Centre