Because of an editing error, an article on Monday about teenage boys and body image misstated the number of boys who were interviewed as part of a recently published survey. It was 1,307, not 2,800. The article also misidentified the academic affiliation of a doctor who commented on supplements and steroids. The doctor, Shalender Bhasin, is a professor of medicine at Boston University School of Medicine and chief of endocrinology, diabetes and nutrition at Boston Medical Center. He is not a professor at Boston Medical Center. And the article misidentified the nationality of the soccer player Cristiano Ronaldo, whose body a teenager quoted in the article said he would like to emulate. Mr. Ronaldo is Portuguese, not Brazilian.