Employers often blame the Internal Revenue Service for the tax, but the rules were written into law by Congress.
And because it is federal law, there are other consequences. One is that employers are not required to offer COBRA benefits -- which allow employees to stay on their employers' plans temporarily after they leave their jobs -- for domestic partners.
The taxes are the result of the interaction of several laws.
First, employer-paid health insurance is tax-free only for employees, their spouses and dependents. "A man and a woman who have not officially gotten married are in the same boat," said Christopher Colwell of the accounting firm BDO Seidman LLP.
Opposite-sex couples, of course, have the option of getting married. Except in Massachusetts, same-sex couples do not. Even if they did, it wouldn't help with the tax treatment.
The Defense of Marriage Act, passed by Congress and signed by President Bill Clinton in 1996, defines marriage for the purposes of federal law as "a legal union between one man and one woman as husband and wife."
It also stipulates that "spouse" refers "only to a person of the opposite sex who is a husband or a wife." The law requires that both these definitions be used "in determining the meaning of any Act of Congress."
Thus, same-sex couples, no matter what the states do, will remain unable to get federal-tax-free health insurance for one partner through the other's employer. A 1997 study by the General Accounting Office (now known as the Government Accountability Office) found 1,049 federal laws in which marital status is a factor. They range from the obvious, such as those concerning joint tax returns, to the obscure but potentially important for certain individuals, such as in determining who gets life insurance proceeds when a federal government worker dies without specifying a beneficiary.
For many couples, the most immediate and painful impact is on health insurance.
While most workers can afford to pay the taxes -- or will struggle to do so because the advantage of employer-paid plans is so great -- some cannot.
It is a "decision people have to make," said Joe Solmonese, president of the Human Rights Campaign, a gay and lesbian rights advocacy group here. At the same time, he said, it's a decision society also should face: "What you have to factor in is the cost of the uninsured . . . the long-term cost of the uninsured partner of the person who makes that tough decision" to forgo coverage because of the taxes.
And those who get sick and are without insurance are likely to end up on some form of public assistance, such as Medicaid.
