I fight people and have opinions! Main thing right now being HEMA, mostly blunted axe + shield sparring. It's mixed-gender and my experience is that men and women are pretty competitive with each other. I've also fenced competitively, which has male and female divisions but men and women practice against each other all the time. Across both sports, height is far, far more important than sex. Like if you're 5'10", you inherently have an advantage in reaching your 5'6" opponent, whether they're male or female. People focus on sex like it's sufficient to equalize genetic advantages and "level the playing field" but think of the difference between the shortest man you know and the tallest man you know. Would you honestly say they're on an even playing field in every sport because of their sex classification?

It really depends a lot on the sport, hormones and time do a lot more than you'd think, and male/female divisions aren't a level playing field to begin with in many sports. Also sure, there is a reasonable discussion to have at a professional level, but in most sports at anything less than the most elite level it's such a non issue. Anyone pushing to police it in kids' sports via genital inspection has lost their minds.