CNN, Same-Sex Spouses Lose Big on Taxes:

Same-sex spouses are paying as much as $6,000 a year in extra taxes because the federal government doesn’t recognize gay marriage, according to an analysis conducted for CNNMoney by tax specialists.

While marriage provides tax benefits for many heterosexual couples, same-sex families don’t enjoy the same perks because they are not allowed to file their federal returns jointly.

The imbalance persists despite increasing acceptance of gay marriage as a legal right. More than 12 states now grant full or partial marriage rights to same-sex couples, and a recent Gallup poll showed — for the first time — that a majority of Americans favor gay marriage.

But not the federal government, which is constrained by the 1996 Defense of Marriage Act. Even as more same-sex couples are able to file jointly at the state level, they are still forced to file as single when submitting federal returns to the IRS.

This means they can’t combine their income and deductions to take advantage of lower tax rates. It’s also harder for them to qualify for certain tax breaks because the credits phase out sooner for single filers. …

To zero in on the tax bill gap between same-sex families across the country, CNNMoney asked H&R Block to crunch number comparing same-sex and heterosexual families according to a variety of scenarios.

(Hat Tip: Ann Murphy.)