But Katzmann penned a concurrence, joined in by Brodie, saying that the time had come to recognize that discrimination based on sexual orientation can be actionable under Title VII.

Southern District Judge Katherine Polk Faillahad dismissed Christiansen's suit after finding those cases required holding that sexual orientation discrimination does not come under Title VII's definition of discrimination “because of … sex.”

Failla noted there were several allegations that Christiansen's supervisor, Joe Cianciotto, was ridiculing him for effeminacy in comments and drawings. But she found Christiansen's complaint centered on discrimination for being gay, not because he failed to conform to a masculine stereotype.

Because Cianciotto also made remarks connecting effeminacy, sexual orientation and HIV status, Christiansen, who is HIV-positive, also brought a claim under the Americans with Disabilities Act, but that was dismissed as well.

The closely watched appeal in Christiansen v. Omnicom Group, 16-748, saw spirited oral arguments in January (NYLJ, Jan. 20).

Christiansen's appeal included support from the U.S. Equal Employment Opportunity Commission (EEOC), which in 2015 changed its opinion and began arguing it was time to recognize sexual orientation discrimination under Title VII.

The EEOC's view is among those currently being weighed by the U.S. Court of Appeals for the Seventh Circuit, which sat en banc in November after vacating a panel's refusal to recognize sexual orientation in Hively v. Ivy Tech Community College , 830 F.3d 698 (2016).

Included among the amici in Christiansen were 128 members of Congress who urged the Second Circuit to reverse course.

The circuit, by per curiam opinion, reinstated the claim based on gender stereotyping under the U.S. Supreme Court's decision in Price Waterhouse v. Hopkins , 490 U.S. 228 (1989), where a female senior manager described as “macho” and “masculine” was told to act, talk, walk and dress more femininely if she wanted to improve her chances for advancement.

Christiansen, the circuit said, alleged Cianciotto described him as “effeminate” to others in the office, “and depicted him in tights and a low-cut shirt 'prancing around'” and “alleges that the 'Muscle Beach Party' party poster, depicting Christiansen's head attached to a bikini-clad female body lying on the ground with her legs in the air, was seen by at least one co-worker as portraying Christiansen 'as a submissive sissy.'”

This was enough to state a claim, the court said, as Simonton and Dawson “merely hold that being gay, lesbian or bisexual, standing alone, does not constitute nonconformity with a gender stereotype that can give rise to a cognizable gender stereotyping claim.”

Katzmann's concurrence outlined how sexual orientation discrimination logically comes within the rubric of Title VII.

“When the appropriate occasion presents itself, it would make sense for the court to revisit the central legal issue confronted in Simonton and Dawson, especially in light of the changing legal landscape that has taken shape in the nearly two decades since Simonton [was] issued,” he said.

“First, sexual orientation discrimination is sex discrimination for the simple reason that such discrimination treats otherwise similarly situated people differently solely because of their sex,” he said, and he would adopt an “associational theory” of sex discrimination.

“I conclude that if gay, lesbian or bisexual plaintiffs can show that they would not have been discriminated against but for the sex of their associates, they have made out a cognizable sex discrimination claim,” he said.

“Finally, sexual orientation discrimination is discrimination 'because of … sex' because such discrimination is inherently rooted in gender stereotypes,” Katzmann concluded.

Susan Chana Lask, who argued for Christiansen, said the decision “gets us our day in court” on the gender stereotyping, and that Katzmann's concurrence “lays the groundwork for the Seventh Circuit to come out with their decision next in Hively.”

“We're very optimistic they will reverse” in Hively, she said.

Rick Ostrove, a partner at Leeds Brown Law, argued for Cianciotto.

“It's time for Congress to act and pass a statute that bans sexual orientation discrimination in the workplace,” Ostrove said Monday. “But as to this case, my client is looking forward to having it decided on the merits because we're confident we will be successful.”

Howard Rubin, a partner at Davis & Gilbert, argued for all defendants but Cianciotto. He declined to comment.