The Supreme Court was going to review a Fourth Circuit decision holding that "sex" for purposes of bathroom usage means "gender identity" under Title IX. However, that decision was based on deference to an Obama administration Dear Colleague letter jointly issued by the Departments of Justice and Education. Since then, the Trump administration issued its own Dear Colleague letter, withdrawing the Obama administration guidance. So, without even considering the underlying issue, the Supreme Court sent the case back to the lower courts to rule on the issue without the 'thumb on the scale' of the Obama administration guidance. We should now see how the lower courts rule based on the statutory text, and whether SCOTUS will still be interested on appeal.
Where does this leave employers? Well, the EEOC has adopted the position that employees must be permitted to use the bathroom that matches their gender identity. Unlike the Title IX guidance for students, the Trump administration has not withdrawn the EEOC's employer guidance yet. And, in fact, that guidance is based in part on an actual EEOC ruling (Lusardi v. Dept. of the Army), which cannot be as easily wiped away as a Dear Colleague letter.
I'll continue to track this issue as it develops. For now, at least at the federal level, the current EEOC position is that employers must allow employees to use the bathroom that matches their gender identity.