Nearly one in 50 US high school students considers themselves to be transgender, and more than a third of those say they attempted suicide in the previous year, according to the first study of its kind by a government agency.
Those transgender students are the frequent victims of violence and bullying, said the study by the US Centres for Disease Control and Prevention (CDC).
The report is the first released by the government health agency delving into transgender-related questions among a large number of students, experts said.
Transgender issues have filled US political debate of late, with the Supreme Court this week enabling the administration of President Donald Trump to bar many transgender people from serving in the military while legal appeals are heard.
Bathroom access has become a major issue in the battle over transgender rights as well, with controversy over whether students should be allowed to use facilities that match their gender identities.
The report by the CDC, the government's leading health agency, found just under 2 per cent of high school students said they were transgender, meaning their sense of gender identity did not align with their sex at birth.
Previous smaller studies have produced estimates of less than 1 per cent to nearly 3 per cent of US teens being transgender.
"It's really important to make sure that people and the government acknowledge and see transgender young people," said Amit Paley, head of The Trevor Project, a suicide prevention organisation for LGBT+ young people.
"This is data that shows that there are so many transgender young people across the country, and it sends the message to transgender youth that they are not alone," he told the Thomson Reuters Foundation.
Thirty-five per cent of the transgender students said they had attempted suicide in the previous year, compared with about 7 per cent of those who did not see themselves as transgender, the CDC found.
The CDC said twice as many reported being bullied and roughly four times as many said they had been threatened or injured with a weapon at school and felt unsafe on their way to and from school.
They were far more likely than non-transgender students to use cocaine, heroin, methamphetamines and prescription opioids as well.