The lawsuit also alleges that CrossFit's policy of having to compete in a person's original birth gender, would require that transgender athletes would have to reveal their personal histories. In essence, that they'd have to "out" themselves, even if they sought privacy, the lawsuit alleges. After her sexual reassignment surgery, Jonsson changed all her records to reflect her sex change to female, including her birth certificate, according to her lawsuit. Jonsson kept her background a secret and did not identify herself as transgender, according to the complaint.Your gender is a cultural construct, but your sex is not. Your gender is how society treats you—do you meet the cultural definition of a man or a woman? Your sex is how medical people treat you—for your health, they can't ignore your sex. You can change your gender, but you can't change your DNA.
So Chloie Jonsson's gender is female, but her sex is male, and she has male physiological advantages like greater upper-body strength that make it unfair for her to compete with cisgender women.
PS. I keep wondering if we'll give up on gender sometime soon. It seems less and less relevant.