She relied on the language and logic of Title VII, and on Supreme Court precedents.

In 1989, for instance, the Supreme Court said discrimination against workers because they did not conform to gender stereotypes was a form of sex discrimination. Being a lesbian, Judge Wood wrote, “represents the ultimate case of failure to conform to the female stereotype (at least as understood in a place such as modern America, which views heterosexuality as the norm and other forms of sexuality as exceptional).”

In dissent, Judge Diane S. Sykes said the majority had overreached. “It’s understandable that the court is impatient to protect lesbians and gay men from workplace discrimination without waiting for Congress to act,” she wrote. “Legislative change is arduous and can be slow to come. But we’re not authorized to amend Title VII by interpretation.”

The Seventh Circuit’s ruling in April created a split among the federal appeals courts, and such disagreements often prompt the Supreme Court to step in. But the defendant in the case, an Indiana community college, quickly announced that it would not appeal.

Legal experts said it was only a matter of time until the Supreme Court addressed the issue.

“The odds that the Supreme Court grants review of this question in the near future are high,” Joshua Matz wrote in April on Take Care, a legal blog. “It is no exaggeration to say that Title VII’s application to gays and lesbians now ranks among the most important open questions in U.S. civil rights law.”

The next case is now on the horizon. It concerns Jameka Evans, who says a Georgia hospital discriminated against her because she is a lesbian. In March, a divided three-judge panel of the 11th Circuit, in Atlanta, ruled that Title VII did not cover discrimination based on sexual orientation.

Gregory R. Nevins, a lawyer with Lambda Legal who represents Ms. Evans, chose his words carefully in discussing whether the odds of winning at the Supreme Court would dim if Justice Kennedy retired.