Domestic-partner benefits motor forward.

Big industry took a big leap into the 21st century June 8 when the nation's three largest automakers announced that they would offer domestic-partner benefits to the same-sex partners of more than half a million employees, starting August 1.

General Motors, Ford, and DaimlerChrysler said they will extend medical, dental, and prescription drug benefits to partners of full-time U.S. employees. (Canadian workers for the Big Three have had such benefits since 1996.) To qualify, couples must be together at least six months and must sign an affidavit attesting that they have a committed relationship.

The announcement is the most sweeping move by a single industry in the United States to offer such benefits, and it follows a growing trend by U.S. corporations to grant such benefits. Currently 98 of the Fortune 500, including the Big Three automakers, grant benefits to the partners of gay and lesbian employees. More than 3,400 public and private employers provide such benefits. Ten years ago, fewer than two dozen companies did so.

The Big Three and the United Auto Workers union had both expressed interest in partner benefits during their normal contract negotiations, said Cindy Clardy, a spokeswoman for Ford's gay, lesbian, and bisexual employees group, GLOBE, which had also pushed for the benefits. "The Big Three have been investigating domestic-partner benefits for some time," Clardy said. "It's equal pay for equal work."

Clardy, an employee recruiter for Ford, said the primary reasons the companies decided to offer the benefits were that the labor market is tight and that a growing number of potential employees are now requesting them.