Puberty can start as young as eight — here's what you need to know 

“For girls, the average age at which it now starts is between eight and 12. For boys, it’s between nine and 13. We’ve more children at the earlier end,” says Gonzalez Ziegler, a Colorado-based clinical psychologist and nationally recognised expert in the US on the intersection of puberty and mental health.

While the development of breast buds in girls and fuller testicles in boys is the first outward sign of puberty, what Gonzalez Ziegler calls “the first wave of puberty” begins in the brain. “It starts silently in the year or two before any physical signs appear. The hypothalamus begins
releasing GNRH, the on-switch for the puberty process. Hormones travel around, giving the nod to the ovaries to start producing oestrogen and to the testes to start producing testosterone.

“When that fully happens, you see breast buds in girls, testicles getting fuller for boys,” Gonzalez Ziegler says. “There’s body odour. By the time you see those physical changes, the child’s brain has been under the influence of puberty hormones for at least a year.”

Gonzalez Ziegler’s book, The Crucial Years, The Essential Guide to Mental Health & Modern Puberty in Middle Childhood (ages six-12), has just been published. 

It offers science-based advice on recognising the first signs of puberty and guidance on navigating the changes that adolescence brings. Once the puberty switch flicks on, four big emotional elements kick in for the child.

“Mood swings and irritability, as well as increased sensitivity and withdrawal,” Gonzalez Zeigler says. “New fears and insecurities develop, which can be about themselves (‘I’m not pretty’), or about others (‘No one likes me’). Children start to have more of an interest in their identity — they want to dress a certain way, listen to certain music.”

While we expect such changes in teens, Gonzalez Zeigler wants parents who see these emotions in their six- to 12-year-olds to think ‘Maybe this is puberty’.

The middle years, between toddler and teen, are often not written about, she says. “But if you’ve a child in early puberty, their [new] interest in identity is because their brain is undergoing adolescent transformation.”

For the child experiencing early puberty, life is not easy. For them, it has taken a tough and incomprehensible turn: “Childhood gets cut short. There are the mood swings, the confusing thoughts and feelings. An eight-year-old girl with breast development would still be considered within the average, [albeit] the early end, but it’s so young. And with that physical maturation, people treat the child differently.”

The early puberty outlier

Elizabeth Nixon, associate professor in developmental psychology at Trinity College Dublin, says anything that sets children apart from their peers can be challenging. 

“Looking at their peers and seeing themselves as the only person to whom this is happening can be very isolating. It creates an emotional distance and feelings of sadness. And the hormonal changes are making them feel more irritable, more down on themselves, emotionally volatile. There’s a greater tendency to have emotional outbursts. Which can lead to conflict with parents.”

Nixon points to the absence of reliable data on early puberty in Ireland, but notes that statistics from the 2021 Growing Up in Ireland study provide some indication. Pubertal development was estimated according to what 13-year-olds self-reported, with separate questions asked of boys and girls. Girls were asked if they had started their periods — most had (90%). But while this figure is substantially higher than that reported by the equivalent study of 10 years before, Nixon says the exact timing of interviews in 2021, as well as differences in methodology, may impact the results’ comparability.

Boys were asked if their voice had changed, which is a less objective indicator of puberty than the start of periods for girls,, says Nixon. Almost one third of boys said their voice had totally changed, 45% said it was occasionally lower, and 14% said it was the same. “These indicators suggest 13-year-old girls were generally more advanced in their pubertal development than [similarly-aged] boys,” says Nixon.

Gonzalez Zeigler points to factors that make the social experience of early puberty different for boys and girls. “The first change that happens for boys is enlarged testicles, which nobody can see. Whereas girls’ first change is breast development, which everybody can see.”

In addition, she says, society sexualises girls, especially at the pubertal stage, which can be anxiety- provoking and disempowering. But boys tend to get positively reinforced for early puberty. “If a boy’s very tall, that’s valued. Being an outlier, of course, can be tough, but the world endorses tallness, well-developed muscles, and growing facial hair earlier. These boys are seen as older, stronger, more capable.”

However, Gonzalez Ziegler acknowledges the significant pressures on boys undergoing early puberty: “They can get pressured to ‘act like a man’, they’re ‘a big boy now’. 

People treat them like they’re older, expect more from them, yet while the boy looks like a maturing young man, emotionally he’s still very young. So, comments from people like ‘You’re going to break girls’ hearts’, can cause real disconnect for the boy inside.”

For children who begin puberty early, there can be an internal out-of-sync feeling. Gonzalez Ziegler says the child may feel, despite all the hormonal changes and the push for identity establishment, that they still want to ‘snuggle up with my parents and talk to my stuffed animals at night’: “They still want to do the emotional things of the age they are. Their brain has one foot in childhood and one foot in adolescence. It can be a very confusing time.”

A shock for parents, too

Parents can also be thrown in to a world of turmoil and confusion when their child enters puberty at an earlier-than-expected age. “They’re seeing a lot more emotions that are surprising to them. They’re saying ‘Oh my God, my child’s acting like a moody teen. One minute they want to hold my hand, the next they’re pretending I don’t exist’. They think ‘Whoa! I’m not ready for this’,” says Gonzalez Ziegler.

In her practice, parents in this situation tell her they feel robbed of their child. “They say ‘I went from having a child to having a teenager. I didn’t have that middle time’. They feel like they’ve lost the child they had.”

Nixon says parents of primary schoolchildren are likely to be no more ready for the onset of puberty than their children are. “Parents would more typically have expected it with the move to secondary school.”

Parents may feel a sense of loss. “Adolescence is typically associated with children seeking more independence,” Nixon says. “The parent-child relationship is likely to go through a period of transition. There can be more conflict in the relationship and the parent may feel rejected by the child: “Their previously lovely, docile child is acting out a bit, there’s distance between them. Parents find this difficult.”

Gonzalez Zeigler says parents have a huge role in helping children navigate early puberty. She says parents need to educate themselves about what is happening for their child and then educating their child, too.

She also stresses the importance of celebrating this new phase with the child. So if a girl has got her first period unexpectedly early, she suggests saying ‘I know we weren’t expecting this, but we’re going to celebrate your body doing what it’s meant to do. And I’m going to teach you how to do this. I promise you: For thousands of years, girls have been taking care of themselves, and you’re going to know what to do.’

Educating the child must encompass the whole gamut of changes puberty brings — physical, emotional, and social. “Because when they [are educated] and understand what’s happening physically, in their brains and socially, they’re left feeling so much more relaxed. It’s very important that the child has a sense that my parent is calm about this — we can do it.”

• The Crucial Years by Sheryl Gonzalez Zeigler, €24.65