Lottie is funny, extroverted and determined; she's one of the most articulate nine-year-olds I've ever met.

She has long blonde hair and a cheeky grin, and she's obsessed with Harry Potter and YouTubers I've never heard of.

Lottie is also transgender; she came out to her parents when she was four.

But none of her friends at her school in suburban Melbourne know she's trans, and her parents want it to stay that way.

"She is still just the same kid — the package is just slightly different," her mum Karen says.

Lottie was born anatomically male, and was initially raised as a boy, with a different name.

But from the age of about three, Lottie gravitated to toys and clothes that are traditionally thought of as being feminine.

"She really did like all the pink stuff. She loved all the fairy wings, fluttery dresses and beautiful fabrics," Karen says.

Lottie gravitated towards toys and clothes traditionally considered feminine from a young age. ( ABC RN: Georgia Moodie )

Karen's partner Michael, who became Lottie's step-dad when she was one, thought it was "just a passing phase".

But by kindergarten, Lottie's behaviour had only intensified.

"I was in dresses and nice necklaces. I didn't really like wearing boys clothes, because it just wasn't me," Lottie recalls.

Karen says she did her best to accommodate Lottie's behaviour, but was "conscious that she might be teased".

"I would force her to wear what we called kinder clothes, which were boy clothes, and she was allowed to wear her tutu or her fairy wings over the top," Karen says.

"Her need to conform to what was feminine and for girls was really as strong as my determination that she fit in and conform with the boys," she adds.

And then one morning before kinder, Lottie told her mum that she wasn't a boy, but a girl.

"To my knowledge, I had never met a trans person, child or adult," Karen says.

"I didn't know that little kids could be trans. I wasn't prepared at all."

An early sense of gender

According to Michelle Telfer, it's very common for children as young as three or four to know they're transgender.

Dr Telfer is a paediatrician and an adolescent specialist, and the director of the Gender Service at the Royal Children's Hospital Melbourne.

"If you ask any child at age three or four, they will tell you absolutely whether they're a boy or girl," she says.

"When you have a trans child who says they're a boy or girl, and it doesn't match their sex assigned at birth, we dismiss it.

"I think all children have a sense of their gender at that age, we just have to trust that children can tell us how they're feeling."

Dr Telfer says it is "totally normal" for children to experiment with their gender and to go through phases of wanting to dress up in a particular way.

But she stresses that the patients she and her team at the children's hospital see are not merely going through a phase.

"If they are persistently, consistently and very much intensely expressing themselves in a particular way — and they become distressed when they're not able to be who they are — that's when we tend to get involved."

'Do I want my child to be a statistic?'

For children as young as Lottie, all the treatment involves is psychological support — questions of medical intervention only come up when young people approach puberty.

The psychological support is crucial, because there are significant risks to the mental health of young trans and gender diverse people, an umbrella term for people whose gender is different from their sex assigned at birth.

In 2017, the Telethon Kids Institute, a medical research institute based within the Perth Children's Hospital, published the results of the largest ever study of Australian trans and gender diverse young people.

They found that 80 per cent of trans young people had self-harmed, and that 48 per cent had attempted suicide.

"Sometimes people talk about medical intervention, surgical intervention, or just psychological support for these young people, and say, 'What if they regret it? What if they change their mind?,'" says Dr Telfer.

"My answer to that is that we need to think about the risks of not intervening. Because the risks of not providing support are that half of them will try to end their life. That's not something we should be able to live with."

For Lottie's parents, Karen and Michael, learning about those dire statistics stopped them in their tracks.

"One in two of these kids will try and kill themselves. I can't do that to my kid, I can't condemn my child to that," Karen says.

"Do I want my child to be a statistic, or do I love them for who they are?" asks Michael. "If they identify in a gender that doesn't match their biology, so be it."

Seeds of acceptance

After months of arguments, Karen and Michael decided to stop fighting so hard against Lottie's gender identity.

They began letting Lottie be a girl at home, but she still had to present as a boy in public.

"We used to say we would support but not encourage," Karen says.

"That came from a position of feeling like we were being blamed for what she was doing."

They were still in this in-between phase when Lottie started primary school.

"She was enrolled as a boy, she was using a boy's name, but she presented in a very, very feminine way," Karen says.

Lottie's mother is now a fierce advocate for trans children and their families. ( ABC RN: Georgia Moodie )

Lottie says some people "didn't understand".

"We would play this game called mums and dads. I would say, 'I want to be the daughter, I want to be the mum'. And everybody would say, 'You need to be the dad.'"

Lottie was bullied; sometimes she'd pretend to be sick so she didn't have to go to school.

"I just felt so sad, because I wasn't being able to be who I am," Lottie says.

Karen and Michael realised Lottie needed to be recognised as a girl in all areas of her life — at home, at school and by family and friends.

They withdrew Lottie from her first primary school, and enrolled her at a new school as a girl, with her newly selected name, Lottie.

'I'm trans and no-one knows my secret'

While the principal and some of the teachers know, no-one else at Lottie's new school knows she's trans.

"I felt so scared, because I thought that people at my new school wouldn't understand. So I'm just going to keep this a secret," Lottie says.

The bullying stopped. So did the pretend sick days.

"Telling myself that I'm trans and no-one knows my secret, that got me out of bed everyday," Lottie says.

Lottie's pretend sick days stopped after she was enrolled in a new school as a girl. ( ABC RN: Georgia Moodie )

Karen is a fierce defender of her daughter's right to be private about the fact that she's trans.

She says it "doesn't affect other kids" and points out that nobody at school should be looking at a child's genitals anyway.

"The only person it makes a difference to is Lottie," says Karen.

"She's the one who has to deal with the fact that her physical body doesn't align with her identity. I don't think discussing it with half the kids in primary school will be a benefit."

Michael says it would "be nice if we didn't have to have that level of caution".

"But there still those who may be unkind, may be unaccepting, may be abusive," he adds.

"I think having that level of caution, particularly while Lottie is a child, serves her interests well."

Lottie says being affirmed as a girl in all areas of her life made her feel "invincible".

"I didn't feel caved in and so sad," she says.

"Every now and then, I would be sad, but then my mum would help me and I'd get back up again and start all over. She's there for me, whatever happens."

A powerful advocate

In fact, Karen has made advocating for trans children and supporting their families her full-time job.

With another mother of a trans child, Karen now runs Parents of Gender Diverse Children, an organisation which advocates for trans and gender diverse young people and provides peer support to their parents.

Since 2016, they have supported more than 700 families around Australia.

Karen says she's "tremendously grateful" for everything Lottie has brought to their lives.

"A four year old set us on this path, and it's been an amazingly empowering and powerful thing in our family," she says.

"She's a happy, gregarious, often loud little girl, who does all the things little girls enjoy doing," Michael adds.

"And none of that is related to her being trans. Her being trans is almost a side issue from her being Lottie."