BIRMINGHAM, England - For most adolescent girls in Britain, shopping for a bra is a rite of a passage into womanhood. But for 14-year-old Alex-Jasper Vaughan, it was one of the most traumatic experiences of the teenager's life.
Vaughan was born a girl but never felt like one. The unease started at the age of 10 and only intensified as Vaughan got older.
Bullied for not wearing a bra by female classmates, Vaughan decided to buy one to stop their snide remarks.
"He absolutely broke down and sobbed at the shops," Vaughan's mother, Jo, told the Thomson Reuters Foundation in the central English city of Birmingham.
"He was grabbing at his chest and sobbing, 'I hate these, I just want them gone. I don't want to grow up, I don't want to be a woman'," she added.
Vaughan is one of a growing number of British children coming out as transgender with some as young as three saying their gender identities do not match their physical bodies, a mental health condition known as gender dysphoria.
But this rise has fueled fears that children may be simply labeled as transgender when they could be gay, lesbian or curious about exploring their gender, activists said.
A UK High Court case last month sparked controversy when the judge ruled that a mother "caused significant emotional harm" to her seven-year-old boy by forcing him to live as a girl.
But sitting next to his mother in a quiet cafe, Vaughan said it was a relief to now live as a teenage boy.
"Alex has always been hidden away with the old me. But the old me is gone - I can truly shine as myself," he said.
Referrals to Britain's only gender identity service for children have more than doubled to 1,419 in 2015/16 compared with the year before, according to The Tavistock and Portman mental health clinic, which runs the service.
Polly Carmichael, a psychologist who heads the service, says in the 20 years she has worked in this field she has seen increasing numbers of children identifying as transgender or saying they do not conform to the gender they were born as.
Though rare, some of her patients are as young as three.
"Young people experiencing gender dysphoria is a real phenomenon," said Carmichael at her London office.
"It can be incredibly isolating ... if you don't feel you belong in a particular category that you've been assigned to. Many adolescents do become very distressed and self-harm."
She said the rise in children struggling with their gender identity is probably the result of greater awareness of the gender spectrum among parents and the children themselves, through the internet and other media.
One mother, who spoke on the condition of anonymity to protect her 10-year-old transgender daughter, said letting her daughter explore her gender before puberty was critical.
"If it turns out to be a phase, great, because that makes life a whole lot easier," she said during a telephone interview.
"But you can only find out if it's a phase by exploring that. Nobody should be forced to be living in a gender role they don't want to be in."
She said her daughter, who came out as transgender last year, has started discussing whether to take 'puberty blockers,' a reversible treatment that delays puberty for children under 16 so they can live as their preferred gender.
For older children, there is an option to take testosterone for those transitioning from female to male and estrogen for male to female transitions.
Both treatments come with risks.
Experts say puberty blockers can decrease bone density, and hormone therapy can lead to infertility in some cases.
Not all young people want to physically transition into the opposite sex. Many simply need space and time to figure out their gender identity, Carmichael said.
Some critics say parents are the ones pushing children to become transgender.
Campaigner Stephanie Davies-Arai said labeling children who do not fit into conventional gender stereotypes as transgender was too simplistic.
"It's presented as if it's a very progressive view ... but it's restricting us into thinking that boys and girls are gender stereotypes," said Davies-Arai, who runs the Transgender Trend website, and struggled with her female identity as a child.
For Alex-Jasper Vaughan, the path is clear. He hopes to be on puberty blockers soon, and then hormone therapy so he can fully transition into a male.
"I understand the psychology behind it a bit more now. I see that he doesn't just want this treatment - he needs this treatment," his mother, Jo, said.
"And ultimately, whatever an individual does, as long as it's not hurting anyone else, why shouldn't we let them do it?"