The four-paragraph letter from Republican presidential nominee Donald Trump's gastroenterologist Harold Bornstein, MD, is still making its way around the Internet.
The letter, which Mr. Trump released last December, attempts to confirm the nominee's physical health. Dr. Bornstein concludes the letter by stating: "If elected, Mr. Trump, I can state unequivocally, will be the healthiest individual ever elected to the presidency."
Here are five things to know about Dr. Bornstein:
1. He is board certified in gastroenterology and internal medicine.
2. He is affiliated with Lenox Hill Hospital in New York City. However, he is not on staff there — even though he signed the letter as a member of the hospital's section of gastroenterology.
3. Although he signed the letter as a fellow of the American College of Gastroenterology in December, he has not been a fellow with the professional society since 1995, according to the Washington Post.
4. He has been the personal physician of Mr. Trump since 1980, according to the letter. Prior to 1980, Mr. Trump was treated by Dr. Bornstein's father, Jacob Bornstein, MD.
5. Dr. Bornstein earned his medical degree at Tufts University School of Medicine in Boston. He went on to complete his residency at Lenox Hill Hospital and his fellowship at the Connecticut-based Bridgeport Hospital.
Update: On Aug. 26, 2016, Dr. Bornstein told NBC News that he wrote the letter — which has been widely criticized as unscientific — in five minutes, while a limo sent by Mr. Trump waited outside Dr. Bornstein's office.