It’s a bit more than ‘could pose risks’ to all kinds of people who do not fit someone’s personal ideal of what a complete stranger looks like. Every human being in the world, even identical twins, is unique in some way. There is no universal rule which says males/females are a specific height, weight, hairstyle, voice etc. The proposal is unworkable.
Rules on single-sex spaces pose risk to trans people’s mental health, UK charities say | Transgender | The Guardian https://www.theguardian.com/society/2025/dec/08/single-sex-spaces-trans-nonbinary-mental-health-charities