The 2020 census will for the first time ask about same-sex relationships.

The Census Bureau last week released details of its upcoming survey.

The survey will ask whether a relationship is “opposite-sex” or “same-sex” and whether the two people are married or unmarried.

The once-a-decade U.S. census added the “unmarried partner” response in 1990. It allowed the bureau to collect information about same-sex couples based on how individuals reported their sex.

Gary Gates, a former research director at the Williams Institute at the UCLA School of Law, told NPR that the previous method was flawed, leading to inaccurate counts.

“Even if only a few different-sex couples make an error where they appear to be same-sex couples, it's a large enough problem that it, for lack of a better word, contaminates the same-gender couples' sample,” Gates said.

The new response is expected to improve the federal government's estimates of how many gay and lesbian couples are living in the United States.

But the Census will not ask about a person's sexual orientation or gender identity.

“If this is about how resources are spent or given to communities and we are talking about the LGBTQ community, not everyone is married or in a relationship,” said Ronald Lewis, a single gay man.

Cecilia Chung, senior director of strategic projects for the Transgender Law Center, said she hopes to see such questions on a future census.

“You know, these are all labels,” Chung, who is transgender, said. “But if we don't have the proper labels when we try to look at the picture, there will be a lot of missing pieces, like jigsaw puzzles.”