American couples will be given the option to define their relationship as either same sex or opposite sex for the first time in the 2020 US census.

The update, revealed in a report by the US Census Bureau, has left many asking why this is the only data being collected about LGBT+ people.

While it will give a clearer insight into how many US couples are in same sex relationships, it fails to recognise those who are single, most bisexual people and all transgender people.

Analytics group Gallup predict that just over four per cent of Americans identify as “LGBT”, or around 10 million people.

Campaigners argue that these statistics would be made clearer if the US census asked specific questions about sexual orientation and gender identity.

“Since the government will only be counting same-sex relationships in the 2020 census, they won't be counting the vast majority of LGBT+ people who aren't currently in same-sex relationships,” said Riley J Dennis, a video creator who identifies as a queer, trans, nonbinary, polyamorous lesbian.

By failing to ask directly and specifically about sexual orientation, those who are bisexual but in same sex relationships at the time of the census will not be marked as LGBT+.

Likewise those who are bisexual but in same-sex relationships will be marked in the same category as lesbians and gays.

Thousands march against Donald Trump in LGBT rights parade Show all 8 1 /8 Thousands march against Donald Trump in LGBT rights parade Thousands march against Donald Trump in LGBT rights parade A marcher hold a sign that reads "Love is Love is Love" on the National Mall with the Washington Monument in the background during the Equality March for Unity and Pride in Washington AP Thousands march against Donald Trump in LGBT rights parade Marchers unfurl a huge rainbow flag as they prepare to march in the Equality March for Unity and Pride in Washington AP Thousands march against Donald Trump in LGBT rights parade Marchers gather to hear speakers at the end of the Los Angeles LGBTQ #ResistMarch AP Thousands march against Donald Trump in LGBT rights parade Gil Mendez, of San Francisco, holds a sign to honor the victims of the shooting at the Pulse Nightclub in Orlando as he marches during the Equality March for Unity and Pride in Washington AP Thousands march against Donald Trump in LGBT rights parade An demonstrator looks on as LGBT members and their supporters take part of the Equality March for Unity AFP/Getty Images Thousands march against Donald Trump in LGBT rights parade A marcher listens to speakers at the end of the Los Angeles LGBTQ #ResistMarch AP Thousands march against Donald Trump in LGBT rights parade LGBT members and their supporters take part of the Equality March for Unity AFP/Getty Images Thousands march against Donald Trump in LGBT rights parade A marcher mugs for the camera during the Los Angeles LGBTQ #ResistMarch AP

The census has also been criticised as there is currently no option to distinguish transgender Americans.

Non-binary people – those who don’t define as men or women – are also left out.

By defining relationships as either “same sex” or “opposite sex” non-binary people are very often excluded, even if they are in a relationship.

“This is moving the needle in the direction, but we must continue to ensure the entire LGBTQI community is represented,” representatives of the North America region of the International Lesbian Gay Bisexual Trans and Intersex Association (ILGA) said. “The 2020 census suggestions continue to marginalize and exclude members of the community who are not recognized in these categories."

Last March, the 2020 census proposal included draft questions about sexual orientation and gender, but the Census Bureau withdrew them, saying that they had been “inadvertently listed”.

“Data collection is absolutely vital for underserved communities, like bisexual and transgender people, who face a distinct lack of funding for tailored services and programs and rely on federally-funded research to reveal the deep disparities these communities face,” said Heron Greenesmith, a bisexual policy attorney for bi communities based in Massachusetts.

Census Bureau researchers hope that the options "same-sex husband/wife/spouse" and "same-sex unmarried partner" will help improve policy making about LGBT+ couples.

A spokesperson for the US Census Bureau said: "The 2020 Census will count the number of same-sex couple households, but will not ask other questions about sexual orientation or gender identity. These topics haven’t met the criteria for adding a new question to the census. If we get an approved request, we’re prepared to test questions about these topics for a future American Community Survey.

"In 2020, our goal is to conduct a complete and accurate census. The Census Bureau remains committed to reflecting the information needs of our changing society. We will continue to examine the effectiveness of decennial census and ACS questions to collect accurate data on America’s people, places and economy."

However for many queer and transgender people the data the census will be collecting is not representative enough.