Page 21 of the ruling:

First, the Enforcement Guidance contravenes Title VII’s plain text by expanding the scope of “sex” beyond the biological binary: male and female. Although Title VII defines “sex” to also include “pregnancy, childbirth, or related medical conditions,” §2000e(k), the Enforcement Guidance concludes that “sex” under Title VII "includes ‘pregnancy, childbirth, or related medical conditions’ and sexual orientation and gender identity." Enforcement Guidance, §I(A)(5) (emphasis added). Notably, the Guidance uses quotation marks around “pregnancy, childbirth, or related medical conditions”—but not “sexual orientation” or “gender identity.” Because neither the plain text of Title VII nor Supreme Court precedent defines Title VII “sex” this broadly. Thus, the Enforcement Guidance lacks statutory or jurisprudential authority to expand Title VII’s definition of “sex” to include these new categories.

Interestingly, this also seems to provide a legal basis to discriminate against straight people and cis people. It’ll be interesting to see how Republicans attempt to close that extra loophole without also closing the loophole for discrimination against LGBTQ people.