Unlike the House version of a health care reform bill, a Senate version approved by lawmakers on Christmas Eve does not recognize gay unions. Senators approved the bill on a narrow 60 to 40 vote.

Lawmakers in each house have approved vastly different bills, but both would subsidize moderate-income people who otherwise could not afford quality health insurance. Those differences will need to be ironed out in a conference committee.

One deviation between the bills is the way gay families are recognized.

The House version approved in November includes Representative Jim McDermott's Tax Equity for Health Plan Beneficiaries Act of 2009, which alters the tax status of health benefits granted to the spouses of gay employees. Under the bill, such benefits would no longer be considered taxable income for the employee. McDermott, a Democrat from Washington, introduced the bill along with Ileana Ros-Lehtinen, a ranking Republican in the House Foreign Affairs Committee, in May.

McDermott told the New York Times that the bill would “correct a longstanding injustice, end a blatant inequity in the tax code and help make health care coverage more affordable for more Americans.”

A report released in 2007 by M. V. Lee Badgett, research director at the Williams Institute, found that gay employees with partners pay, on average, $1,069 per year more in taxes than would a married employee with the same coverage.

“Collectively, unmarried couples lose $178 million per year to additional taxes,” the report says. “U.S. employers also pay a total of $57 million per year in additional payroll taxes because of this unequal tax treatment.”

Representatives also approved language that would make it illegal to discriminate based on “personal characteristics” in the delivery of health care.

But neither of these provision are present in the Senate version.

Allison Herwitt, legislative director of the Human Rights Campaign, the nation's largest gay rights advocate, told gay weekly The Bay Area Reporter that the group is “disappointed that the Senate did not include any of the LGBT-specific provisions that we have been working to advance throughout the health reform debate.”

Herwitt said her group would continue to fight for the gay provisions as legislators reconcile the bill's differences in committee.