U.S. Civil Rights
According to the latest Census, one in five gay couples is raising children. REUTERS

The number of gay Americans who are living with their same-sex partner has doubled in the past decade to almost 650,000, with more than 130,000 of them registered as same-sex married couples, according to figures released by the U.S. Census Bureau on Tuesday.

About 131,729 gay and lesbian couples checked the husband or wife boxes on their 2010 census forms, the first time they could so since Massachusetts became the first state to legalize gay marriage in 2004.

Aside from the Bay State, gay couples can now obtain marriage licenses in Connecticut, Iowa, New Hampshire, New York, Vermont and Washington, D.C.

The figures released by the Census Bureau on Tuesday are a revision of earlier estimates released over the summer. The agency originally reported that there were 349,377 same-sex married couple households and 552,620 same-sex unmarried households, which the Census Bureau reports was caused by coding errors that resulted in an exaggerated tally.

In a statement, the agency said the data was derived from two questions on the 2010 census -- the relationship to householder and the sex of each person. The Census Bureau said the wrong box may have been checked for the sex of a small percentage of heterosexual couples, artificially inflating the numbers of same-sex couples in the U.S.

As scientists, we noticed the inconsistency and developed the revised estimates to provide a more accurate portrait of the number of same-sex couples. We're providing all three -- the revised, original and ACS [American Community Survey] estimates -- together to provide users with the full, transparent picture of our current measurement of same-sex couples, said Census Bureau Director Robert Groves.

The 2010 ACS survey estimated gay and lesbian married couples at 152,335 and unmarried couples at 440,989, which is closer to the results of the revised Census Bureau statistics.

The number of same-sex couples rose considerably from the adjusted 2000 figure of 358,390, according to the Census Bureau.

However, researchers believe the estimate may be as much as 15 percent lower than the actual number of same-sex couples in the U.S., due to social stigmas or other concerns about confidentiality.

About 51 percent of same-sex couples in 2010 were women, while nearly one in five of gay couples were raising children at home.

Washington D.C. had the highest share of households with same-sex couples, both married and unmarried, at almost 2 percent. The capital was followed by Vermont, Massachusetts, California, Oregon, Delaware, New Mexico and Washington State. Meanwhile, North Dakota, South Dakota and Wyoming had the smallest proportion of same-sex couples at less than one-third of 1 percent.