The Defense of Marriage Act (DOMA) could cost the federal budget of the US over $6 billion (£3.9 billion) between 2005 and 2014, according to a report which predicted that the federal law, which bans equal marriage, could be costing money.

The study by the Congressional Budget Office, was conducted in 2004, and predicted that repealing DOMA could save the federal budget up to $1 billion (£660 million) in each year from 2005 to 2014.

It reads: “The potential effects on the federal budget of recognizing same-sex marriages are numerous….

“The Congressional Budget Office (CBO) estimates that on net, those impacts would improve the budget’s bottom line to a small extent: by less than $1 billion (£660 million) in each of the next 10 years.”

Those critical in the past have used finance as a reason for not repealing DOMA, and extending the 1,100 benefits to then married gay couples, saying that doing so would cost money, but reports, and the study by the CBO suggest otherwise.

AmericaBlog reports that the savings constituted by the repeal of DOMA would be between $4.9 billion (£3.2 billion) and $6.2 billion (£4.1 billion) over ten years.

The study went on to predict that the tax revenue from legalising equal marriage would grow from $400 million (£264 million) yearly to up to $700 million (£460 million).

It said: “Revenues would be slightly higher: by less than $400 million (£260 million) a year from 2005 through 2010 and by $500 million to $700 million (£330-460 million) annually from 2011 through 2014.”

Finally, the study looked at the potential cost, or outlays, for the government, of legalising equal marriage, predicting that spending would eventually decrease as a result.

“Recognizing same-sex marriages would increase outlays for Social Security and for the Federal Employees Health Benefits (FEHB) program, CBO estimates, but would reduce spending for Supplemental Security Income (SSI), Medicaid, and Medicare. Effects on other programs would be negligible. Altogether, CBO concludes, recognizing same-sex marriages would affect outlays by less than $50 million (£33 million) a year in either direction through 2009 and reduce them by about $100 million (£66 million) to $200 million  (£120 million) annually from 2010 through 2014.”

Several recent polls have shown that support for equal marriage in the US has risen to an all time high. One poll, conducted by the Washington Post and ABC News, found that 58% of Americans now support the legalisation of same-sex marriage. Another, by CNN, found that 53% of Americans support it. 

This week a poll by an American Christian group found that 64% of respondents agreed that “it is inevitable that same-sex marriage will become legal throughout the United States,” while 80% disagree that employers should be allowed to discriminate based on sexual preference.

The Supreme Court is due on 27 March to hear evidence around the case of the Defense of Marriage Act (DOMA), which defines marriage as between a man and a woman, passed under President Bill Clinton in 1996.