Census Won't Count Gay Marriages

The policy will, for example, require that the couple's children be listed as having single parents, Gates said. And it will cause the census to undercount families, defined as two or more people in the same household related by birth, adoption or marriage, he said.

In Massachusetts, 10,490 same-sex couples were married between May 2004 and August 2007, according to state figures. California, which began same-sex marriages last month, does not keep similar figures. A ballot initiative would amend the state Constitution to ban same-sex marriage.

Peter Sprigg, vice president for policy at the nonprofit Family Research Council, argued that the Census Bureau's policy makes sense both demographically and legally. He said his group will "vigorously defend" the Defense of Marriage Act if critics try to overturn it.

"We believe that marriage is intrinsically the union of a man and a woman," Sprigg said. "The reason marriage is a public institution in the first place is that it brings together men and women for the reproduction of the human race and to encourage mothers and fathers to cooperate in raising to maturity the children produced by their union."

Curtis likened the Census Bureau's stance to something out of the Cold War era.

"It's like we've been Photoshopped out of the picture," she said. "How long is the federal government going to pretend we don't exist?"

Staff researcher Madonna Lebling contributed to this report.