At least in the UK, data from the Ministry of Justice shows that trans-identifying male prisoners are significantly more likely than other men to be incarcerated for sex offences.

There is also no data whatsoever indicating that if a man calls himself a woman, then he poses any less risk to women than other men.

I agree that prisons need to stay sex-segregated, or revert back to being so where authorities have made this abominable ideological error of incarcerating men in the women's prisons.