In many ways, Ruby – a pseudonym she chose herself – is still a child. She plays with dolls, draws for hours and says sex sounds like a “gross” undertaking – this despite her mother’s best attempts to pitch the story of human reproduction in a positive light. But for Ruby, the blithe physicality of childhood – of being your body rather than assessing it, managing it, worrying about it – is already a thing of the past.

Another of Ruby’s concerns is that her sanitary pad or, worse still, blood, might show through the body-hugging fabric of her leotard. Ruby’s first period arrived when she was just nine and her great fear is that if her peers find out what her forward-thinking body is up to, they will be “grossed out”. Her opinion of her own breasts: “I don’t like them. They’re very jiggly.”

At Ruby’s dance school, wearing shorts or a skirt over the top of a leotard, which might provide a greater sense of containment and privacy for a self-conscious little girl, is not permitted.

The school probably doesn’t give much thought to the tender sensibilities of girls of 10 and younger who are deep in the clutches of puberty. Such girls have always existed but their needs have been easy to neglect because they’ve been a tiny minority. That, however, is changing.

So many more girls are running to Ruby’s developmental timetable that what has been considered “normal” for four decades is now a subject for debate. There are no definitive figures on the phenomenon – and certainly no Australian ones – but endocrinologists all around the developed world are seeing “more and more” of it, says Kate Steinbeck, medical foundation chair of adolescent medicine at Sydney University and an adolescent endocrinologist at The Children’s Hospital, Westmead. Periods among primary schoolers are so well recognised in the US, for example, that Kotex has introduced “U Tween”, a range of sanitary pads that come in colourful packets and are aimed at girls aged “eight to 12”.

No one knows why it’s happening, but there are plenty of theories, ranging from rising rates of obesity to chemical contamination to early life stress. Perhaps the only certainty is the trend provokes a lot of anxiety, particularly for parents.

Gina* was seven and in year 2 at primary school when she casually mentioned a new discovery to her mother. “Oh, you know I have hair,” she said, pointing towards her own crotch.

“I said, ‘No you haven’t’ … then when she showed me, I nearly died,” says Joanne. Gina, however, couldn’t understand what all the fuss was about. “She just thought it was a bit funny. She was too young to even comprehend it.” Joanne, who knew nothing about early puberty, presumed her daughter had some kind of serious medical condition. “It was frightening,” she says.

Girls who present with signs of early puberty are typically put through a barrage of medical tests. They include a brain scan to exclude the possibility of a pituitary tumour, which can cause early puberty; a wrist scan to establish bone density, which is a measure of physical development; a pelvic ultrasound; an external genital examination; and intensive blood testing to determine levels of the sex hormone estradiol, a key player in female sexual maturation. The process tends to be “very distressing” for parents and children alike, says Steinbeck.

Gina’s results put Joanne’s concerns about her daughter having a medical condition to rest and then presented her with a whole new set of worries. Puberty was underway. “How do I prepare a seven-year-old to get her period? That was my worst fear,” says Joanne. “Can you imagine her going to primary school and having to change her pad? I mean, they’re still babies at that age. They don’t understand what’s needed in terms of the hygiene if you’re not with them.” When a paediatric endocrinologist said medical suppression of puberty was an option, Joanne didn’t hesitate.

The drugs used to stall puberty are gonadotropin-releasing hormone analogues, originally developed to treat prostate cancer. Leuprorelin acetate (brand name Lucrin) is the most commonly used in Australia, says Steinbeck. Goserelin acetate (brand name Zoladex) is another. The drugs are generally well tolerated, but are not without side-effects, and they’re given via a long-acting injection, which is an uncomfortable procedure compared to your typical childhood inoculation.

Gina, who is now 11, had Zoladex injections for three years and has been off them for six months. She still hasn’t begun menstruating, but that’s normal. It can take up to a year for puberty to get back on track and over the finish line.

Joanna says the whole experience doesn’t appear to have affected Gina “in any way”. That may be in part because, for most of the time, she was kept in a state of blissful ignorance. She had always been very prone to stomach aches, says Joanne, “and whether or not this was the right thing to do, I just told her she was having the needles for her tummy aches”.

When puberty hit Charlotte, she was subject to a different type of ignorance. She got her first period at 10, had no idea what it was and literally thought she was “bleeding to death”. She was also teenager-tall and filled a C-cup bra. She recalls being at the supermarket with her mother “and men would literally crash their shopping trolleys looking at me”, she says, now 25. “Sexual attention from adult men really screws with your head when you’re a child, but I learnt really early to shut out people who looked at me. I still do it.”

She went on to develop anorexia in her first year at high school. The eating disorder was, she says, jump-started by a brutal comment from an older boy, who said, “I’d like to f… your big arse.” The comment came on top of years of peer harassment, including being referred to as Pam, as in Anderson.

Charlotte was lean, but recalls thinking, “I’ve got to get rid of this big arse and I’ve got to get rid of these big boobs. I’ve got to get skinny.” With the benefit of therapy, she’s made a full recovery. “Early puberty was not a nice experience but it made me who I am,” she says. She has two daughters of her own who, needless to say, will know full well they’re not dying when their periods arrive.

Early puberty is a diabolical subject to pin down. That’s in part because, whether it comes early or otherwise, it is an epic, complex, years-long transition rather than a single event. The science around early puberty also seems subject to more than its share of caveats and debate. Steinbeck, for example, says papers on early puberty tend to make her “anxious” because she’s aware of the frailties of the data on which many of them rely. Some of it is quite old and much of it relies on reports from parents about their own children’s physical development rather than blood tests, which would be more accurate but also far more expensive and difficult.

Since the 1960s, it has been considered fairly typical for a girl to get her first period between 12 and 13 – a radical drop from 100 or so years earlier, when the typical age was 16. There are also, however, variations across ethnic groups. Black American girls, for example, tend to hit the transition earlier than white American girls, who in turn tend to hit it earlier than European girls. There is no equivalent Australia-specific data.

Whenever it comes, that first period is pretty much puberty’s last hurrah, marking the end of a process that typically started 18 months earlier, with breast budding, followed by pubic and underarm hair. Sometimes, however, the pubic hair comes first and sometimes the gap between breast development and the arrival of the first period is longer or shorter. There is also a broad continuum that defines what is considered less typical, but still quite normal. Current guidelines used by specialists such as Steinbeck say a girl of eight showing the first signs of puberty is at the earliest end of the normal spectrum.

Girls are 10 times more likely than boys to experience early puberty, according to research published in Frontiers in Endocrinology. Boys are five times more likely than girls to experience delayed puberty.

Valerie reckons she must have been “in denial” when her husband first mentioned that their seven-year-old daughter, Amy, was showing signs of breast development. “I went, ‘Nah, nah, no’ … but, of course, she was.”

Looking back, she says Amy, who is an overseas adoptee, must already have noticed it herself, because she had started hunching her shoulders. Unbeknownst to Valerie, Amy had also discovered pubic hair. She might not have known what it was, but she clearly didn’t like it because she’d been shaving it off. When Valerie eventually took Amy to the doctor, she was told the child’s breast development was within the realms of normal and that she was unlikely to start menstruating until she was 11. But, just after she turned nine, Amy got her first period.

Valerie says her daughter is a reserved and self-conscious child who, at nine, had no comprehension of what was happening to her. “I didn’t know what to tell her,” says her mother. “She wasn’t mentally ready for it.” For the first few days, Amy seemed to cope and even claimed wearing a pad was “fun”. But then the ongoing reality hit home. “I went to pick her up from school and she had bled through the uniform because she hadn’t changed her pad,” says Valerie. “This is a little girl. We’d only just sorted out her wetting the bed and went straight on to periods.”

Amy began to withdraw. She’d been an athletic child but stopped going to gymnastics, showed no interest in having friends over and would spend hours alone in her room. On the quiet, Valerie was taking it hard herself. “I felt I had let her down, that something I had done must have brought this on,” she says. She sought guidance from counsellors, one of whom suggested she hadn’t adequately welcomed Amy’s womanhood. Valerie scoffs at the new-age sentiment. “Moving into womanhood is a great thing, but I couldn’t rejoice for her because it was just too bloody young.”

When a paediatric endocrinologist suggested Zoladex, “I jumped at it,” says Valerie. She had also become aware of research that links early puberty to a range of troubling issues she was keen to avoid.

“There is a fair bit of evidence … that girls who hit puberty earlier tend to have higher rates of mental problems, such as depression and anxiety,” says George Patton, professor of adolescent health research at Melbourne University. “They also tend to have higher rates of behaviours that are risky for their health, such as substance abuse, early sexual activity, self harm and eating disorders. These things are all linked to puberty generally, and girls who enter puberty earlier enter the risk period earlier.”

For Amy, the Zoladex injections brought a world of relief. “I would be devastated to find out that there is some long-term side-effect,” says Valerie, “but I think this was a good decision for Amy.”

In Ruby’s home, medical suppression is a tempting possibility on hold. Ruby doesn’t want it and, with support from a trusted classmate, is coming to grips with primary school pad management. She is, however, very concerned about the pending school camp, mainly because her new cycle is unpredictable. “She is struggling so hard to try to fit in with her peers and not let them know what’s going on,” says Sophia, her mother. “She says to me, ‘What if it goes through my pyjamas, Mum?’ It’s all this pre-thinking she shouldn’t have to do as a child. She should be able to just … be.”

Sophia says she lies awake at night wondering whether Ruby should take up the breathing space the drugs would offer. But she is also worried about medicating a young girl who is not sick, worried there might be future health consequences for Ruby, and worried her daughter would be more upset by the injections than she had been by her period.

Steinbeck says medical suppression can keep an endocrinologist awake at night, too. “Nobody would quibble if you [gave it to] a five-year-old with breast development who was looking at getting her period. But in these borderline cases, seven to eight, it’s really hard. If a little bit of breast development is considered normal at eight, what if you have a little bit of breast development at 7½? It’s a grey area.”

The staff at Westmead, as elsewhere, do see girls as young as five entering puberty, but such extreme cases do not appear to be increasing. And, like early puberty, extremely early puberty is not an exclusive 21st-century phenomenon. There is no more confronting an example than Peru’s Lina Medina, the world’s youngest confirmed mother. Now 79, she gave birth to a son, via caesarean section, four months before her sixth birthday.

There is no simple answer to why girls seem to be entering puberty earlier. Research links it to all sorts of factors, such as obesity, low birth weight, social disadvantage, early stress and immigration from a poor country to an affluent one, including overseas adoption. Girls who are vision-impaired are more prone to earlier puberty, says Steinbeck, as are girls who do not live with their biological fathers. It’s a perplexing and messy list, and many of the factors, such as social disadvantage and obesity, for example, are difficult to separate. The exact mechanisms behind the links also remain theoretical or unknown.

Body weight appears to be the clearest link. Research shows heavier girls tend to enter puberty earlier. The drop in the typical age of first period between the 1840s and the 1960s is largely attributed to improved nutrition and heavier bodies. Why this might be so is not known in absolute terms, but it is at least in part about the body recognising that enough body fat has accumulated to support a pregnancy. “There are certainly a lot more overweight children and adolescents around,” says Steinbeck.

Another mystery is US research that suggests that the age at which breast development begins is falling. American author Florence Williams has written about this at length in her book Breasts: A Natural and Unnatural History. As she points out, breast tissue is particularly sensitive to environmental influences, and this gives some credence to arguments that endocrine-disrupting chemical compounds, such as bisphenol-A, phthalates and parabens, which mimic the sex hormone oestrogen, are influencing puberty’s pacing. These chemicals are ubiquitous, often unlabelled and found in everything from shampoo to food packaging to garden hoses.

Not everyone, however, is convinced by this argument. Serious industrial accidents have demonstrated that endocrine disrupting-chemicals can influence sexual development, but their effects in the general environment remain a matter for debate. “There are lots of questions around endocrine disrupters, but I don’t think we have any evidence,” says Steinbeck.

Peter Gluckman, a renowned New Zealand paediatric biologist, isn’t even confident earlier breast development is real. “I’m not absolutely convinced by the data. In part, we have just got more sensitive about recording when breast development occurs.”

Whatever its causes, early puberty is not a terrible thing for every girl who experiences it. “Some families deal with it very well,” says Steinbeck. Patton, too, says “many kids, probably a majority, are going to go through puberty early and they’re not going to have problems”.

As a nurse, Clare knew exactly what was going on when her eight-year-old daughter, Andreea, complained of a lump and tenderness in her chest. She knew it was breast budding, knew periods were likely within 18 months, knew about Zoladex and was also aware of the unsettling research about early puberty and mental health. Clare describes Andreea as a clever, kind, organised and highly “self-motivated” child. She plays soccer, netball and three musical instruments, and happily rises before dawn several times a week for swimming training.

“I thought if Andreea started menstruating in year 4, that would do my head in,” says Clare. “She is a super-involved kid. She is in to everything. I didn’t want [early periods] to stop her being as involved as she was. But I felt the injections would have been a real setback, too.

“We just put Andreea and the way she felt about it all to the forefront,” continues Clare. “Once we weighed up what would be worse – [drugs] or periods – and we saw she was in an okay place if she got it early, we decided no, we wouldn’t try to suppress it.” Andreea is now 12. Confoundingly, while she has breasts that qualify for a bra and an adult quota of pubic hair, she still has not begun menstruating. It seems unlikely she’d be too concerned if she did. Many of her friends have now caught up – a matter of great importance when you’re 12.

Earlier puberty seems somehow less remarkable when you consider that our reproductive capabilities do not build up as we mature, but are in place from birth and, in fact, have to be restrained. The only thing keeping us from the horrific prospect of reproductive capability from the get-go is an exquisitely tuned genetic brake located in the brain. At a time it deems right, based on unknown environmental and genetic information, the brake eases off and the process completes itself. There is even a “mini puberty” in young babies – which manifests as enlarged genitalia in boys and slight breast enlargement in girls – which then subsides. Midwives and GPs often have to reassure parents that what they’re seeing is quite normal, says Steinbeck.

A team of US scientists believe they have – at least in a mouse model – identified the key genetic elements within the brain that form the puberty brake in girls, and how those elements interact. Their report was published in the March issue of Nature Neuroscience. A commentary published in the same issue, by US scientist Margaret McCarthy, says the discovery is important because it provides a target within the brain on which to test the possible effects of that long list of factors – from phthalates to obesity – suspected of tampering with the brakes.

In the meantime, we do not appear to be heading towards a generation of Lina Medinas. “It’s important that, as scientists, we don’t feed into community anxiety that girls are going to come into puberty younger and younger, because there is no evidence,” says Steinbeck. Gluckman has similar views. He remains fairly convinced that any continuing fall in the age of puberty is the decelerating, tail-end of our evolutionary response to improved health and nutrition. He would prefer to see communities focus on preparing young people for puberty – with all its attendant vulnerabilities – whenever it might arrive. “How many people feel comfortable to talk to an eight-year-old girl about periods and puberty? People feel awkward about it.” That needs to change, he says.

Indeed, celebrating womanhood, as Valerie’s counsellor suggested, may be far less important than simply teaching all children about the way humans mature in a positive, matter-of-fact and timely way. Guidelines for teaching sexuality in Victorian primary schools, for example, say, “All children need to know about puberty before it happens.” For a growing number, that is between seven and eight.

When children are told about how human bodies change in an age-appropriate way, and early enough, it becomes “just one more new thing in a world of new things,” says Margie Buttriss, a consultant sex educator who visits schools in Victoria. “But if you wait until they are maturing themselves, it becomes about them and it’s much more embarrassing and difficult for them to hear.”

And it’s not just the early developers themselves who need that information, says Bernadette Duffy, a lecturer and researcher at the University of Ballarat’s school of health studies and education. “Everyone needs to know about [puberty] and everyone needs to know it can happen early. It’s about setting up a safe environment that says it’s okay to grow and develop when you do,” she says.

* The names of all the children and parents have been changed to protect privacy.

Lead-in photograph by Nick Cubbin, styling by Maia Liakos, hair by Allison Boyle. Model: Mikayla Medworth from The Extras Agency; Bra from Bras 'N Things.

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