The UCLA School of Law’s Williams Institute, which studies gender-identity issues, pegs the size of the U.S. transgender population at 700,000; how many are athletes is difficult to determine. The most contentious recent case was in November 2010. Kye Allums, a starting guard for the women’s basketball team at George Washington University came out before his junior year, making him the only open transgender Division I athlete. Allums said, "Yes, I am a male on a female team. And I want to be clear about this: I am a transgender male, which, feelings wise … I feel as if I should have been born male with male parts.From Sports Illustrated's preview of The Undefined Path of the Transgender Athlete by Pablo Torre (@SIPabloTorre) & David Epstein (@SIDavidEpstein).