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Preparing for the Full-on Fours

By Steve Biddulph 2 min read

Boys don’t just develop at a different rate to girls. They also have unique developmental stages, triggered by hormonal shifts, which are only just being understood. The “full-on fours” is the first of these.

Luteinising hormone levels in four-year-old boys pulsate every day in exactly the way that testosterone levels do in adults, though we do not know why. So, in a sense, four is the start of the puberty process. Whether this directly or indirectly causes the behaviour changes we have no idea.

In 2017, Professor Kate Steinbeck, a specialist in children’s endocrinology at the University of Sydney, offered her explanation of the full-on fours stage:

“Is there an alternative explanation for boys’ behaviour at this age, which parents regularly report? We see differences in boys’ and girls’ brains and behaviour well before puberty. Rises in testosterone in the womb and during the mini-puberty in the first six months of life likely explain these.

“Studies that look at behaviour in four- to five-year-olds . . . show boys and girls this age generally have different ways of playing and communicating. Boys’ play is generally more physical. Girls generally have more socially interactive play, and are more articulate.

“Interestingly, girls with congenital adrenal hyperplasia, who are exposed to high levels of testosterone in the womb, tend to have more ‘rough and tumble’ play styles, consistent with a testosterone effect on early brain development.

“So how might being four or five change boys’ behaviour? At this age, children learn how to interact with others, understand another’s needs, share and to deal with new and unfamiliar situations. Boys may respond more physically and be less able to articulate what happened. Learning how to regulate their emotions is an important skill for children to develop. Parents can model good emotional regulation, make sure children have regular daily routines, enough time to practise play and enough sleep. Praising positive behaviour and not overreacting to minor attention-seeking misbehaviour also helps.

“Persistent and distressing behaviours in a child may signal underlying anxieties, reaction to family stresses or be a result of adversities when they were younger. So, if you are concerned, seek professional advice.

“For all children, we need to prioritise time to play. That could mean space, action and permission to be noisy and boisterous.”

So, in her words, it is testosterone, but the causes are earlier in life, only coming to the fore through the stresses of being four!

There is something we need to remember here. For 99 per cent of human history, we were a very physical and lively species—we moved about all the time. In hunter-gatherer society, four-year-old boys are just leaving toddlerhood and start rapidly acquiring the stamina, strength and amazing physical dexterity needed for their adult lives. (I lived with and studied hunter-gatherer people in the mountains of West New Britain, Papua New Guinea, in the 1970s, and from the very first day I was astonished at how capable and independent small children were, often accompanying us on long journeys without any sign of fatigue. Nothing saddens me more than seeing the cooped-up tiny spaces that urban children now live in, or the way our schooling forces kids to stay sitting for long periods in the same place.)

At four, boys start onto their real boyhood and for many of them that includes a great need for movement and action. It’s a serious parental challenge to find ways for our boys (and girls) to express their physical energy safely and sociably, and still stay connected to them and their feelings so they know they are loved. In fact, the whole challenge of being male, lifelong, is learning that it’s possible to be energetic and safe, boisterous and thoughtful, adventurous and responsible.

Understanding your boy’s nature is the first step. The second step is engaging with him and helping him to learn how to steer it well. That takes patience, empathy and good-humoured persistence.


Steve Biddulph is a psychologist and parenting expert with 40 years experience. He has changed the nature of boys’ education, brought a generation of fathers into hands-on engagement with their kids and given mothers the confidence to love their sons and not be afraid of them.

Extract from Raising Boys in the 21st Century by Steve Biddulph (Finch Publishing), available nationwide.


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