One of the biggest issues I feel never gets talked about when it comes to the politics surrounding trans rights is how to protect both sex and gender as classes.
For example, let's look at a common issue that is brought up, restrooms. Restrooms are currently segregated, but a question needs to be asked, are they to be segregated based on sex or gender? One cannot 'protect' both simultaneously, as if you have them segregated by sex then regardless of gender identity you will use the restroom of your biological sex, but if you segregate based on gender then the initial reasons for creating these 'separate but equal' spaces is being violated, protecting people based on sex.
The same thing can be said about sports. They initially became segregated due to the sex differences, but the push for trans-rights has the push for having the segregation be based on gender instead.
To me, it seems that one cannot have both sex and gender as protected classes, and so we have to ask why one should be prioritized over the other. Should sex be a protected class or should gender? If sex, why not gender? If gender, why not sex?