LONDON (Thomson Reuters Foundation) - Young people attacked the global advertising industry on Thursday for failing to represent them, as a major new poll indicated almost a third of those aged between 18 and 21 in the United States now identify as LGBT.

For millennials, aged between 22 and 39, the figure was 20 percent, found the survey - shared exclusively with the Thomson Reuters Foundation in advance of publication - of 11,500 people by Kantar Consulting, part of the major advertising group WPP.

Yet many young lesbian, gay, bisexual or transgender people said their sexuality was being ignored by major brands, leading to feelings that they were being excluded from society.

“It would be good to have more representation as it would make me feel more accepted,” Rex, an 18-year-old Irish student told the Thomson Reuters Foundation on Thursday.

“We are a minority, so you do notice it when you are represented and I’d love to see more of this.”

The visibility and acceptance of the LGBT community is growing in the United States and Europe, with gains including the legalization of gay marriage and the easing of rules allowing people to amend the gender on their birth records.

But many businesses have yet to tap into the market. The Kantar research estimated LGBT buying power in the United States alone at $1 trillion in 2016 – almost equal to African-American or Hispanic consumers.

One 19-year-old Londoner, who wished to remain anonymous, said he had never seen an advert directed at or including younger transgender people. If there were, “it would show that it is normal and accepted to be transgender”, he said.

LGBT-themed adverts have become relatively common in the United States and Europe, but many under-30s complained that they were aimed at more middle-aged gay consumers, rather than the youth market.

“To me, it does feel like ads are behind the times,” said Annie Bell, a 26-year-old communications worker in London.

“They are stuck on these very stereotypical versions in which LGBT people don’t really fit in.”

Companies are starting to take notice. The vodka brand Smirnoff recently launched its “We are Open” campaign, which featured gay people over the age of 21.

“This is a long-term commitment for us,” said Luke Atkinson, vice president of global communications for Smirnoff.

“We can make a difference in our actions and communications to the LGBT community, making their lives and their socializing more fun and more vibrant. And because their socializing and nightlife culture is our culture, it’s a win-win.”

The dangers of under-representation are clear, said Sean Howell, co-founder of Hornet, an LGBT social network that commissioned the Kantar survey.

“When young people don’t see themselves represented, they are being pressured to be something that they are not and that can lead to depression, suicidal thoughts and actual suicide. It’s something we should talk about.”