The overwhelmingly supportive response to Jason Collins, who came out last week as the first openly gay male athlete playing in a major American team sport, is an encouraging measure of the nation’s civil rights progress. But his barrier-breaking announcement a dozen years into his N.B.A. career also carries a reminder of a reality millions of gay people live with every day: being open about their sexual orientation could put their job and career at risk.

A pair of landmark cases pending before the Supreme Court will help decide the future of same-sex marriage. But even if the justices do the right thing and issue a broad ruling legalizing same-sex marriage nationwide, that would not prohibit workplace discrimination, a profound impediment to real equality. The lesbian, gay, bisexual and transgender community remains vulnerable to employment discrimination in more than half the country.

Only 21 states have laws barring employers from refusing to hire people or firing them because of their sexual orientation, and only 16 of those have inclusive workplace nondiscrimination laws that cover bisexual and transgender people as well as gays and lesbians.

Mr. Collins’s announcement coincided with the reintroduction in the House and Senate of the Employment Non-Discrimination Act, an overdue measure to outlaw employment discrimination based on sexual orientation and gender identity. It has been stalled in Congress for years. But the idea that job applicants and employees should be judged on their professional credentials and the caliber of their work, and not be penalized because of who they are, is a basic fairness principle, and one that polls indicate most Americans support.