A chromosomal abnormality. Typically, affected cells have one y and two x chromosomes (contrast the y and x of cells in a normal male). People with this non-disorder often exhibit vaguely sinister androgyny and an independent and empirical worldview unrestrained by popular gender expectations.
That tall angry guy with the hourglass figure has Klinefelter Syndrome. He's sterile. He diverts his creative instincts toward art, vigilantee suicide missions, and hormonal spazzing. Don't fuck with him, he's wild.