This gives the "transgender" person an opportunity to disguise his intent. Allowing biological men who "identify" as "transgender" to use girl's restrooms and showers gives "predator" males greater access to their potential victim.
When any one group has rights that override the rights of another group, they are wrong. Biological males who identify as transgender do not have a right to neutralize women's rights. When biological men who identify as transgender are given the right to use girl's restrooms and showers, they have effectively eliminated women's right to safety and privacy.
So what is the solution for biological males who identify as transgender? This is a small percentage of the overall population, so these individuals can use the nurse's restroom or teacher's restrooms until separate transgender facilities can be installed.