Miles Everitt, 18, thinks himself lucky to have been well supported by his school when he came out as transgender. Growing up female, he’d always preferred to wear boys’ clothes and play the male character in online games; at secondary school, after he cut his hair short, many teachers assumed he was a boy. It was seeing a trans character on Hollyoaks and then reading blogs by young trans people on Tumblr that made him realise he could be transgender.

Three years ago he came out in a video he posted on Facebook. His mother’s response was to go into his school at Wadebridge, Cornwall, to talk to Miles’s “awesome” headteacher, Tina Yardley: “She went in, and said, ‘My child wants to be called Miles,’ and she [Yardley] was like, ‘That’s fine. We’ll make sure all teachers call him that from now on’.”

Miles says: “It meant my teachers were calling me the correct name and pronouns, and it means a lot to all trans people to be accepted and addressed in the right way.”

As well as respecting Miles’s new name and pronoun, Wadebridge school agreed he could use an accessible changing room for PE and the male staff toilets. Miles, who is now at college and plans to study paramedic science at university, is taking testosterone to complete his transition and is planning gender reassignment surgery.

Schools are supporting increasing numbers of transgender students, using a variety of guidance from the teaching unions and charities such as Mermaids (which has a grant of £35,000 from the Department for Education to deliver training to 35 schools).

This rise is reflected in referrals to the children’s Gender Identity Development Service (Gids), run by the Tavistock and Portman NHS trust, which increased by 1,978% – from 97 in 2009 to 2,016 in 2016-17. Of those children, 70% are biologically female.

Bernadette Wren, a clinical psychologist at Gids, says many young people seen by the service have been bullied or self-harm, and a number are on the autistic spectrum.

Hessle Academy in Yorkshire, which has three students transitioning from female to male, has used Mesmac, a local charity, to train staff on transgender issues, while Barnardo’s has delivered assemblies and workshops to year 8 and 10 students. The school has also set up an email address that students can contact anonymously about their gender identity.

Sarah Young, the school’s head, sees the increase in numbers identifying as transgender as largely positive: “These young people are being given the opportunity and support to come and talk to somebody earlier than they might have done in a previous time.”

Now a fierce national debate over gender self-identification is spilling over into guidance for schools. On one side are those who think women and girls should be entitled to safe spaces that aren’t automatically accessible to trans girls. On the other are those who believe all who identify as female should have full access to female toilets and changing rooms. Recently, Girlguiding leaders have protested about a policy that allows boys identifying as girls to share tents with girls on overnight trips.

Profound disagreement has arisen about what schools should do. Should they, in the words of a widely used toolkit from the Allsorts Youth Project in Brighton, “make visible and celebrate trans people”? Or take the “watchful waiting” approach advocated by the Transgender Trend pack, which warns schools to be “aware of the risk of ‘social contagion’ from celebrity trans internet vloggers who glamorise medical transition”?

Stephanie Davies-Arai, a parenting adviser, launched the Transgender Trend resource pack in February half-term, thinking it would barely get noticed. Instead, she says: “It just blew up”. The LGBT lobby group Stonewall accused Transgender Trend, the organisation Davies-Arai set up two-and-a-half years ago, of spreading “damaging myths, panic and confusion”, and advised local authorities not to use the pack. On Twitter, people piled in, with one describing the pack (which had been checked by lawyers) as a “modern edition of Mein Kampf”.

Davies-Arai says she took an interest in the subject because as a child she had felt herself to be a boy, and she didn’t think it was a good idea to label children like her as transgender because she believes that in some cases, these feelings resolve naturally by the end of adolescence.

While the Allsorts advice states that “trans pupils or students should have access to the changing room that corresponds to their gender identity” and that in PE lessons, students “should be enabled to participate in the activity which corresponds to their gender identity if this is what they request”, Davies-Arai argues that shared changing rooms present difficulties for some girls. Few teenage girls will be willing to admit that they feel uncomfortable sharing a changing room with a biologically male student, she says.

She points out that the technical guidance on the Equality Act for schools suggests offering students “private changing facilities, such as the staff changing room or another suitable space” – the approach taken at Miles’s school.

Susie Green, CEO of the charity Mermaids, disagrees, saying the debate about single-sex toilets seems “engineered to whip up fear” and is equivalent to “arguing people of colour shouldn’t be allowed to use the same toilets as white people in case they make them dirty”.

Claire Birkenshaw, a transgender former headteacher, says the wide range of different advice creates confusion and conflict. “There needs to be clear statutory guidance for schools that incorporates the views of experts from education, the medical profession, the Equality and Human Rights Commission and trans people,” she says. “Rows about a vulnerable and marginalised group in education are not helpful.”

The EHRC is planning to issue guidance of its own next month, something Birkenshaw welcomes. “Schools want to support the transgender young person, but at the same time they’ll be reflecting on how other children may feel, on how staff are going to feel and parents.”

Davies-Arai says her broader concern is that by affirming students’ gender identity, schools may be nudging them down a route that can lead to cross-sex hormones and life-changing surgery without enough time to reflect. Teachers, she says, “are essentially being forced to collude in an experimental approach towards children with gender dysphoria”. She adds: “You can support children and accept them, without affirming their belief that their body is ‘wrong’.”

Adele Robinson (not her real name), a head of year at a secondary school, shares Davies-Arai’s worries. The school has had 12 children, all girls, come out as transgender in the past 18 months. The majority, she says, have autism, and some have experienced sexual abuse.

When they come out, she says, they have brought in information sourced from Tumblr blogs and YouTube videos. Although her team does its best to “support every child in a loving, kind and compassionate way”, she feels that staff are too frightened to challenge what she sees as harmful practices: “We have chest binders worn in school, which is horrible. If a child was cutting, they would be straight in with a counsellor. Yet damaging developing breast tissue goes unquestioned. It’s a gross failure in terms of child protection.”

Green disagrees, and argues for a biological underpinning to transgender identity: “If a child or young person consistently, insistently and persistently states their feelings, to ignore, punish or repress their gender identity would effectively be reparative therapy.”

At Wadebridge school, Miles’s former headteacher says: “You just have to put the child at the centre of everything to enable that child to feel comfortable and supported. The biggest message I’d want to get out is that this is not a transgender issue, this is a supporting young people issue.”

The best way of providing support is, however, something that the two sides seem unlikely to agree on.

• This article was amended on 15 May 2018 because Wadebridge is in Cornwall, not Devon as an earlier version said.

