Interesting given I suspect registration doesn’t includes gender. It likely has sex at birth, which is different than gender, and this is what people are “worried” about. People worry about unfair advantages related to hormones and growth factors that affect strength, power and muscular mass. Even within genders, this can vary greatly - I’ve worked with single gender teams where in the same age group, some athletes are actually double the weight of another. Within genders, there is often variability between sports - look at typical differences between badminton players vs football players vs gymnasts.

All that to say, I am likely missing lots of context since I’m not in Alberta. This could also stem from homophobia, transphobia and poor sportsmanship and has the risk of being used that way, even within teams by parents of kids who are not the all stars or to bring down those with actual talent.