IDK, it's a statement based on false premises:
"As scientists, we are compelled to write to you, our elected representatives, about the current administration’s proposal to legally define gender as a binary condition determined at birth, based on genitalia,"
". The relationship between sex chromosomes, genitalia, and gender identity is complex, and not fully understood. There are no genetic tests that can unambiguously determine gender, or even sex."
"In intersex people, their genitalia, as well as their various secondary sexual characteristics, can differ from what clinicians would predict from their sex chromosomes. In fact, some people will live their entire lives without ever knowing that they are intersex.5 The proposed policy will force many intersex people to be legally classified in ways that erase their intersex status and identity, as well as lead to more medically unnecessary and risky surgeries at birth. Such non-consensual gender assignment and surgeries result in increased health risks in adulthood, and violate intersex people’s right to self-determination."
It's complete nonsense, because it's only referring to sex discrimination by public bodies under Title IX, not a wider transgender status, and because there's nothing in the statement that suggests that people with intersex conditions will not be able to change their gender, rather what it's saying is that for Title IX sex discrimination purposes, people's sex will be considered to be that noted at birth unless they have genetic evidence to contradict that.
In cases where intersex conditions are known to have variant gender identities, it's very hard to imagine that this would be the case.