When Jack Green was four years old, he told his mother 'God made a mistake, I should have been a girl'.

“As soon as he was old enough to toddle he was in my wardrobe, trying on my clothes. When he was two his nursery rang and said ‘Jack doesn’t play with the other boys, when the dressing up box comes out he goes straight for the pinafore’. I said ‘I know, let him get on with it, he’ll grow out of it,’” Susie Green recalls.

But that didn’t happen. Once a cousin had researched dysphoria and alerted Jack to the possibility of gender reassignment surgery there was no equivocation about what needed to be done. On her 16 birthday, with her mother by her side, Jack Green went into surgery in a hospital in Thailand and woke up as Jackie.

The number of young people seeking gender reassignment in Britain is at an all-time high. The Tavistock and Portman NHS Trust says the number of children referred to them for assessment has risen from 97 in 2009 to 208 last year, and is on the up.

For the parents of children with gender issues, like Susie Green, a 43-year-old IT consultant in Leeds, the emotional toll can be great. By the time Jackie went for an assessment and started ‘blockers’ - injections designed to stop the release of hormones - at the age of 14, she had attempted to kill herself 7 times. According to Mermaids UK, a support group for the people with dysphoria and their families, feelings of loss, guilt and confusion for those on the sidelines are par for the course.

In her case, Green says, it had been obvious since her child was very young that “something wasn’t right”, and seeing Jack struggle to tally a feminine sense of self with an increasingly masculine body made fully supporting her eldest child her only option. Her younger children only ever knew Jack as Jackie so that made things easier. But for Jackie’s father it was more difficult.

“He really struggled to deal with it,” Green says. “Jackie’s dad was insistent it was a phase, but going to the clinic opened his eyes to the fact you can’t make a child something they are not. One of the first things the therapist said was ‘would you make your younger sons wear a dress?’”.

In the UK, the minimum age for trans-man and trans-woman surgery is 18, with a long period of assessment before it would ever be approved. As many as 80% of children who were diagnosed with dysphoria before they reached puberty did not have the condition after puberty, according to the Endocrine Society (although some campaigners dispute that figure), so it is general practice to wait until the mid-teens before undergoing treatment.

Most people affected display symptoms in childhood. However, according to the Gender Identity Research and Education Society, the growth in adult referrals is growing at a rate of 11 % per year, while “presentation for treatment among youngsters is growing more rapidly at 34% per annum”.

Even if isurgery is approved – a procedure costing £10,000 a pop - before undergoing surgery candidates must live as their preferred sex full time for at least a year, a process known as ‘real life experience’. After that, there is 18 months of preparatory hormone treatment, along with therapy.

Jackie started the transition when she was 10: “The clinic told us to allow her to dress up at home but to remain a boy outside of the house to make it easier in case she ever wanted to go back.” One of her friends, a teacher, said “Don’t let him do it, ‘it’ll be awful, he’ll be annihilated at school’. I knew there would be issues but Jackie was going downhill. There was no way she could cope with pretending to be something she wasn’t.”

In the end, Susie Green’s child was kicked, spat at, and taunted by kids and adults.

At that point things got so bad that, when Jackie was 14, she went with her mother to Boston for the necessary ‘blocker’ injections, before flying to Thailand to have the operation two years before it is legal in the UK. In total the process cost around £20,000. But it was worth every penny, she says. Now Jackie has a longterm boyfriend, whom she met months after the op; she has a job as a sales assistant and is pursuing a career in modelling. Her story is being told in a BBC3 documentary ‘ Transsexual Teen, Beauty Queen’ which airs tonight.

“If she’d waited until she was 18 and gone through the NHS, theoretically we’d still be waiting but actually I don’t think she’d be here,” Susie says. “She’d told me: ‘I won’t grow into a man. If that starts to happen, I will kill myself’.’ ”

In statistics

The number of young people seeking referral for is growing by 34% per year

The number of children referred to the Tavistock clinic for assessment rose from 97 in 2009 to 208 last year