Alex realised he was also transgender while researching for Jessica

Her parents split up when she was a baby and she lives with her mother Ella, and Ella's partner Alex

The stepmother of one of Britain's youngest transgender schoolgirls is now living as a man, the family has revealed.

Jessica, nine, was born a boy but has identified as a girl since she was very young, and has been going to school as a girl for more than a year.

Her parents split up when she was a baby, when her mother, Ella, began a relationship with a woman called Alex shortly afterwards, with Jessica calling Alex her 'step mum'.

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Jessica, nine, (pictured) was born a boy but has identified as a girl since she was very young, and has been going to school as a girl for more than a year

But in February last year, after researching what Jessica was going through, Alex realised that he was also transgender and started living as a man.

The family's story was revealed on the BBC's Victoria Derbyshire programme, which started following Jessica, and another transgender girl Lily, seven, last year and revisited both families on today's show.

All of the names of those involved in the programme were changed to protect their identities.

'I didn't want to do anything about it until I felt that Jessica and the family were in a more stable place - I thought now was the time I needed to be more true to myself I guess,' Alex told the programme.

'I've pretty much felt the same as Jessica, but didn't understand or know until I researched what was going on with Jessica. Then, I instantly knew myself.'

According to figures obtained by the BBC, in the last year 167 children aged 10 or under have been referred to clinics, almost double that of the previous year.

The family's story was revealed on the BBC's Victoria Derbyshire programme, which started following Jessica last year and revisited the on today's show. Jessica is seen here talking to the presenter

Jessica has been having nightmares about growing a beard and dying a man, the programme heard

This number includes three children who are just three years old, with the increase being attributed to society becoming more accepting of transgender children.

Interviews with both Jessica and Lily were carried out with their parents' permission and show how the girls' lives have changed since they first appeared on the programme, and how their school friends had been supportive of their transitions.

Lily, who has been dressing in girls' clothing since January last year, told the programme that she had marked the start of her life as a girl with 'skirt day' at school, and was thrilled when a classmate told her she looked nice.

Jessica's mother said that school was going well for her daughter, who is about to have her name legally changed with her father's permission, but added that the schoolgirl had been having nightmares about growing a beard and dying a man.

She has started asking her parents for hormone blockers, which can be given to transgender children to stave off the physical changes that come with puberty, giving the child more time to decide if they want to live as a man or a woman.

I'm not going to end up being a boy forever, because I will be a girl and I know that. Sometimes it doesn't feel like that though Jessica

Both Lily and Jessica have gender dysphoria, which the NHS describes as being where 'a person experiences discomfort or distress because there is a mismatch between their biological sex and gender identity.'

Their parents had initial wondering if the children's preference for girls' toys and dresses might have been a phase, but their desire to live as girls is just as strong after several years.

In her previous interview, carried out when she had been living as a girl for two months, Jessica had explained that she found being a boy 'really frustrating for me. It felt like I didn't fit in.'

Asked why being a boy would make her unhappy, she said 'Because I just don't feel like I should be a boy - I feel like I'm in the wrong body.'

The NHS does fund gender reassignment surgery at an average cost of around £10,000 but they are only offered for the over-18s, while hormone therapy can being at 16.

For younger children, the NHS will fund counselling and therapy sessions at the Tavistock and Portman NHS Trust, the UK's only centre specialising in gender issues in under 18s, which runs clinics in North London and Leeds.

Usually this treatment consists of one-to-one sessions with the child and a psychotherapist, while parents are also offered counselling and support.

The Tavistock trust said it ‘would not generally consider it helpful to make a formal diagnosis in very young children’, and any physical intervention is not considered until a child approaches puberty.

Jessica said she finds it difficult when people treat her as a boy, and can struggle to control her temper.

'I'm not going to end up being a boy forever, because I will be a girl and I know that,' she said. Sometimes it doesn't feel like that though.'