Story here.

A federal appeals court on Monday ruled that a 1964 civil rights law bans anti-gay workplace discrimination. The decision rebukes the Trump administration which had argued against a gay worker in the case and hands progressives a win in their strategy to protect LGBT employees with a drumbeat of lawsuits.

The dispute hinges on whether Title VII of the Civil Rights Act of 1964, which bans discrimination on the basis of sex, also bans workplace discrimination due to sexual orientation.
This is the most interesting part of the decision, in terms of the reasoning:

"A woman who is subject to an adverse employment action because she is attracted to women would have been treated differently if she had been a man who was attracted to women," the majority wrote in an opinion led by Judge Robert Katzmann. "We can therefore conclude that sexual orientation is a function of sex and, by extension, sexual orientation discrimination is a subset of sex discrimination."