Preconception Antidiabetic Drugs in Men and Birth Defects in Offspring: A Nationwide Cohort Study

(Abstracted from Ann Intern Med 2022;175:665–673) Diabetes mellitus is known to compromise sperm quality and is associated with impaired male fertility. Metformin is a first-line oral diabetes medication that has been shown to improve markers of semen quality in obese men but reduces serum testosterone levels independently of glycemic control.