Don't forget non-physical sports such as chess, segregated by sex not gender. Most articles I found described these rules as "anti-trans"
, but other articles point out that odds are stacked against women and girls. "The researchers considered how the important people in girls’ lives—coaches and parents—may be biased against them when assessing their potential, even at a young age, and how these perceptions may help explain the huge gender gap in who plays chess."
Also, on equestrianism - yes, women compete against men, and yes, they often win. But that doesn't mean that it's an equal sport. Anyone who rides will know that girls and women massively outnumber males as leisure riders, or in lower-level competitions. But this proportion is not reflected in elite competitions. There are many articles about this, e.g.
https://inside.fei.org/fei/sports-forum/2024/session-documents/session-six "While females make up around one-third of ranked athletes in Jumping, this percentage decreases sharply at the top levels. In the top 100, female representation dropped to 20% by 2022, and to just 6.8% in the top 30. A similar trend is observed in Eventing, where although women are the majority overall, their representation diminishes at the highest ranks, dropping from 72% overall to 53% in the top 30 in 2022."
https://theconversation.com/equal-but-not-the-same-equestrian-sports-unisex-approach-hides-inequity-64054
https://heelsdownmag.com/why-arent-more-women-on-the-podium/
It's not entirely clear why this is, but a variety of factors have been suggested, including sponsorship preferences for men, time off for pregnancy and motherhood for women (which can sometimes affect eligibility), periods and the standard uniform of white breeches.
Anecdotally, I'd add that there are some preferences amongst horse-riders, in that many women are more interested in horses as pets to nurture, and men tend to be more competitive. (The reasons for this would be material for a study!) Then, it's a dangerous sport, and it's well known that men tend to be braver or more reckless; also, many women I know are less brave after having children.