America's Tyson Gay, who placed second, celebrates with the US flag after the men's 100-meter final during the World Athletics Championships in Berlin, 2009. Gay said on July 14, 2013, that he has tested positive for a banned substance and that he will pull out of the world championships to be held in August in Moscow. Anja Niedringhaus/AP/File
Sherone Simpson (l.) of Jamaica crosses the finish line to win the women's 100-meter at the ISTAF Berlin Grand Prix athletics, Aug. 22, 2010. Former 100-meter world-record holder Asafa Powell and teammate Simpson have tested positive for the stimulant oxilofrine at the Jamaican championships and were just recently notified, their agent, Paul Doyle, said on July 14, 2013. Fabrizio Bensch/Reuters
Tyson Gay (l.) of the US and Asafa Powell from Jamaica compete in the men's 100 meters during an IAAF World Athletics Final at Thessaloniki's Kaftanzoglio stadium, Greece, 2009. Thannasis Stavrakis/AP/File
Baltimore Ravens linebacker Ray Lewis looks around before their NFL Super Bowl XLVII football game against the San Francisco 49ers, Feb. 3, 2013, in New Orleans. News reports that linebacker Lewis used deer-antler spray, which contains a banned substance, dominated pre-Super Bowl coverage. Lewis denied using the spray to help him recover from a torn arm muscle. Dave Martin/AP/File
Lance Armstrong of the US rides past the Arc de Triomphe during the 20th and final stage of the Tour de France cycling race between Arpajon and Paris in 1999. The seven-time winner of the Tour de France, admitted in an interview with Oprah Winfrey to doping for years. Laurent Rebours/AP/File
New York Yankees starting pitcher Roger Clemens throws to Kansas City Royals' David DeJesus in in 2007. Clemens told Congress in sworn testimony: 'I have never taken steroids or HGH' (human growth hormone). His former trainer testified that he did. Clemens would later be tried for perjury - and exonerated. Ed Zurga/AP/File
Former baseball player Barry Bonds leaves federal court in 2011 in San Francisco after being found guilty of one count of obstruction of justice. The jury failed to reach a verdict on three other counts that the home run king lied to a grand jury when he denied knowingly using steroids and human growth hormone. Noah Berger/AP/File
US sprint star Marion Jones wins the long jump with a 7.13 meter jump at the track and field invitational in Carson, Calif., in 2004. Jones admitted in federal court that she used steroids before the 2000 Olympics. She was later stripped of three gold and two bronze Olympic medals. Lucy Nicholson/Reuters/File
Former St. Louis Cardinal Mark McGwire testifies along with Sammy Sosa (l.), Jose Canseco (2nd l.), Rafael Palmeiro (2nd r.), and Curt Schilling before House Committee on Government Reform to discuss steroid use in Major League Baseball in 2005. Andy Nelson/The Christian Science Monitor/File
BALCO founder Victor Conte holds up one of his nutritional supplements he sells, at his office in Burlingame, Calif., 2003. Federal authorities raided BALCO, a California company suspected of supplying illegal performance-enhancing drugs to professional and Olympic athletes. The BALCO scandal would eventually reveal that doping in sports in endemic. Paul Sakuma/AP/File
Ben Johnson of Canada (r.) leads the pack to win the 100-meter dash finals at the 1988 Summer Olympic Games in Seoul. American Carl Lewis (c.) was second and Linford Christie (l.) of Great Britain was third. Johnson was later stripped of his medal for testing positive for a banned steroid. AP/File
Top US sprinter Tyson Gay acknowledged that he has tested positive for a banned substance, rocking the track-and-field world. But the news also points to how much has changed in antidoping.
Ben Johnson, Marion Jones, and ... Tyson Gay?
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