Several male athletes have previously come out after retirement, including Amaechi, the NFL's Esera Tuaolo and Major League Baseball's Billy Bean.

BBC: NBA player Jason Collins comes out as gay

Fast forward to Esera Tuaolo.

FORBES: The Historical Prelude and Eventual Significance of Jason Collins Coming Out

While Collins is the first male athlete in a major North American professional league to come out while intending to keep playing, several have previously spoken after they retired about being gay, including the NBA's John Amaechi, the NFL's Esera Tuaolo and Major League Baseball's Billy Bean.

NPR: 'I'm Gay': NBA Player Jason Collins Breaks Barrier