Okay next question, is the risk to women from a 10 year old trans girl using women's spaces greater than the risk to a 10 year old trans girl were she expected to use men's spaces?
Any young child or vulnerable person, including a ten year old of either sex, is safer in a women-only space or in a mixed sex space than in a men-only space.
The single sex space is safer for anyone because men are much more violent and predatory than women.
The mixed sex space is safer because adult women tend be vigilant to protect children from predatory men.
Mixed sex facilities are more dangerous for women and girls than female only spaces. This is because males are much much more violent and predatory than females.
None of this means that females should lose female only spaces.
Making all spaces mixed sex does make life safer for vulnerable males, that is true, but it also inevitably makes all females more vulnerable.
Provision of mixed sex or some kind of supervised space for vulnerable males in addition to female-only spaces would keep the most people safe.
There is considerable evidence that when everything is mixed sex then more women are hurt than males are saved.
Every single culture on the planet keeps women separate from men for some things. Men teach boys to respect women's privacy and dignity by not busting into those spaces even though they physically could if they tried.
Currently some males seem to think they have found a loophole and are seeking to exploit it to come into the female spaces. Women have noticed and are saying no. The men are starting to notice too and they are saying no too.
To reduce the risk to vulnerable males a campaign directed at men to reduce violence towards others would be good. Building design to make it harder for men to predate undetected would also be useful.