From the proudly displayed stars and stripes to the rows of lockers outside the classrooms and the uniformed security guard at the main entrance, it seems just like any other high school in New York.

But here and there are clues that this is a unique place: a notice in the corridor proclaiming “Equal rights for New York transgender workers”; the rainbow flag and the after-school classes in vogueing.

This is Harvey Milk High, the world’s first school designed for gay - or rather LGBTQ (lesbian, gay, bisexual, transgender, and questioning) - pupils. It is the same as any other school, but different. And it has the same problems as any other school, but different.

Naihomy Abreu has only seen two fights in the two-and-a-half years she has been at Harvey Milk, a stark contrast to the nine in one day she once witnessed at her previous school. But that does not mean there are never any problems.

“There is a little bullying here and there, but every school has that,” says Naihomy, 18. “The way people bully here is not like to fight. It is more sarcastic comments. We call it throwing shade.”

Pupils here have had to cope with more than a bit of shade since the publicly funded high school opened in 2003. At times they have had to walk past demonstrators carrying placards outside the lower Manhattan building saying “God Hates Fags” and “Go to Hell Harvey Milk Students”.

Hannah Devane first enrolled aged 15 after experiencing difficulties in her Manhattan school. “I came out and people were bullying me,” says the 18-year-old. “There was a rumour going round that `Hannah likes all the girls in school’.

“I was like, `Oh my goodness.’ It was very hurtful. I reported harassment and nothing was done. It was just like, `Move on, transfer, it’s better for you. We can’t help you here. You’re wrong, they’re right. This school is not for gay people.’”

She was told about Harvey Milk High by her social workers and transferred three years ago. “It has just been the best for me ever since,” she says. “The teachers are more caring. This is a school supporting LGBTQ but also it is for everybody. The school is just a great place.”

Pupils do not have to be lesbian, gay, bisexual, transgender or questioning to go to Harvey Milk, although they have to accept its ethos.

Orville Bell, an English teacher also in charge of admissions, says interviews are held “to make sure that everybody understands what everybody is in for”.

About five pupils apply for every place at the school. Applicants are asked about their attendance records and grades at previous schools and why any problems might have occurred, but they are not expected to reveal their sexuality.

Its name may be a giveaway, but the New York education department’s official web page for Harvey Milk carries only one passing reference to the LGBTQ community. Ask how many teachers at the school are gay and the pupils immediately volunteer that all of them are, bar two.

But the principal, Alan Nolan, quickly cuts in to say it is up to teachers to “self identify” and that he has “a number of staff who identify as heterosexual”.

It feels like a deliberate bid to downplay the school’s LGBTQ nature. If so, one possible motive is that when the school received public funding in 2003 religious groups threatened the school’s existence with a lawsuit accusing it of illegal discrimination. “That was the result of a lot of ignorance and prejudice,” says Mr Nolan.

But it is not just on religious grounds that some people have found the idea of a school for gay pupils hard to comprehend. Aside from the issue of whether segregation is a sound policy, it raises the question of whether the start of high school might be too early for pupils to choose a school based on their sexuality.

But high school in the US does not begin until ninth grade, when pupils are at least 14. And Harvey Milk High is one of a small number of what are known in New York as “transfer schools”, set up to provide alternatives to pupils who are struggling or have dropped out of one of the city’s mainstream high schools.

To be admitted to a transfer school pupils must have spent at least a year enrolled at a conventional high school. This raises the minimum age to 15. And in the last academic year only two of the school’s 100 or so pupils were at the minimum age.

Mr Nolan insists his portrayal of the school as mixed is more than just window-dressing. Two years ago a third of pupils identified as straight. In the last academic year that fell to around one in 10. Asking how many of the heterosexual pupils could be described as “questioning” would be “an intrusion of privacy”, he says.

Naihomy came out when she was in ninth grade at a private Catholic high school. A friend spotted an Avril Lavigne picture on her folder and Naihomy admitted that she was gay.

By the end of the year most pupils accepted it, but then she moved to a school of 3,500 pupils and found herself “lost in the system”. She ended up missing a year and a half of school through truanting and was told by her counsellor “a big school environment is not for you”.

The 18-year-old vividly remembers her first day at Harvey Milk High. “I walk in and I am just like, `What!’ When I come upstairs I am just like, `Oh my God!’” she says.

“I am greeted with a gay flag up next to the American flag and I am like, `This is the school for me!’ Because even in my public high school I was out, but there was still a lot of people that didn’t like it.”

Nevertheless, she says it was the size of her previous school, rather than her sexuality, that was the deciding factor in opting for Harvey Milk.

New York public schools can have up to 4,000 pupils, and after doing well in junior high Anthony Martinez also found the high school atmosphere intimidating.

He came out after he started a relationship with a boy at high school. But, like Naihomy, the 17-year-old insists being gay was just one factor in his desire to move to Harvey Milk.

“I live in one of the most ghettoised places in Brooklyn and I really don’t have a problem,” he says. “But I felt if I didn’t get what I wanted I wouldn’t be happy.

“School wasn’t giving me what I wanted and on top of that I was getting harassed, and I don’t need that.”

Both Naihomy and Anthony have thrived under Harvey Milk’s nurturing philosophy. “Our mission is wonderful,” says Mr Bell. “Not only are we going to cater for their academic development, but we are also catering to their emotional development and for whatever trauma and scars that were experienced from previous educational institutions.

“They are not going to experience that here. We are simply accepting and welcoming. We are all about making sure they are educationally and emotionally healthy to go on and continue with their lives.”

He also aims to provide a positive example to pupils who are gay. “I say, `My name is Orville and I am gay,’” he says. “I think it is very important that they see a successful, educated role model who is very proud of being different, because many of my students had not had that exposure before.”

Critics might suggest there is a risk of creating a gay ghetto for young people and that isolating them will leave them ill-equipped to deal with the wider world when they leave. But Samantha Rivera fiercely rejects the charge.

The 18-year-old is another refugee from a vast high school - 3,800 pupils in her case - and insists Harvey Milk is not about segregation. “It is for those students who were having a really, really hard time in their previous schools,” she says.

“You want to be in a place where you are safe without having to worry about any outsiders coming in and making you feel uncomfortable about anything.”

She says going to Harvey Milk means she can focus on her work, without the threat of disruption. “I am here in this high school for the same reason that a thousand other kids are in the other high schools. I want to graduate and I want to learn,” she says. “Just because I go to Harvey Milk does not mean I am there because I am gay.”

The school is coming under pressure to lower its minimum age. Mr Bell says he has recently had to turn away 13 and 14-year-olds applying for places. He believes that as young gay people “self-identify” earlier, the school may need to respond.

This earlier coming out is a positive sign, says Anthony. “The world is becoming more accepting,” he says. “We are normal. There is nothing wrong with us - it is just we like a certain type and it is what it is.”

For Naihomy, even though LGBTQ young people face problems, society has still progressed. “It is not a crime to say `I’m gay’, and once you realise that it is easier to come out,” she says.

But for Mr Bell, the most positive development of all would be for the school to cease to exist altogether. “There shouldn’t be a Harvey Milk High School and we hope one day that there won’t be one,” he says. “All our students should be able to be safe in every single high school in this city. But that is not the reality.”