Louganis is of Samoan-Swedish ancestry and was adopted when a few months old by a white couple who also adopted another child. He began competitive diving when he was 10. He had a troubled time as a teenager with drink and drugs and found diving an outlet which he could practice alone.
He won a silver medal in the 1976 Olympics, the 1982 World Championship, Olympic gold medals in springboard and platform diving in 1984 and 1988, the 1987 Pan-American gold medal in both events, and retired in 1989 having won 47 national championships as well. He is acknowledged to be the best diver in history.
He is also dyslexic, gay and HIV+. Contrary to one source (Kehoe, below), he does not stutter. Since retiring from diving he has begun an acting career.
Dever, Maria, and Dever, Aileen. Relative Origins: Famous Foster and Adopted People. (Portland: National Book Company, 1992) Who's Who in America, 1996 Microsoft Encarta 98 Encyclopedia, 1993-97 Louganis, Greg, and Marcus, Eric. Breaking the Surface. (New York: Plume, 1996). Also available as a VHS cassette (1997) Milton, Joyce, and Marchesi, Stephen. Greg Louganis: Diving for Gold. (New York: Random House, 1989) (Step-Up Books) "Louganis, Greg," Current Biography Yearbook, 1984 "Greg Louganis - the Home Page." [Includes portraits]. Available at:  Kehoe, Thomas David. "Famous People Who Stutter." [from Stuttering: Science, Therapy & Practice (1977)?]. Available at:  Reibstein, Larry. "Public Glory, Secret Agony," Newsweek, 6 March 1995. Also available at:  Personal correspondence