In the first of a series about young people around the world as part of the BBC's Generation Next season, the BBC's Robin Lustig asks what does it really mean to be an adult?
According to the dictionary, an adult is "a person who is fully grown". A child, therefore, is "a person between birth and full growth". And an adolescent? Trouble.
Moody, argumentative, sometimes aggressive, why are teenagers so difficult? Or perhaps they're just confined to the richer countries of the industrialised world.
If you've been brought up in poverty, and you're expected to be helping to put food on the table by the time you're 14, there's not much opportunity to argue about the length of your skirt or the colour you want to dye your hair.
What I've discovered, making a series of programmes for the BBC's Generation Next season, is that there's much more to childhood and adulthood than biology. Yes, a child of 14 or 15 may have gone through puberty, may have grown breasts or a beard, but an adult? I don't think so.
We've spoken to dozens of children, adolescents and adults on several continents for this series, trying to get to know the generation next in line for adulthood, the generation that in decades to come will be running this planet of ours. Here's what some of them told us about growing up:
- John, 14: "The day I'm adult is the day I can do whatever I want without my parents or someone like that preventing me."
Shruti, 15: "I feel pretty much like an adult but sometimes I feel I'm not sure."
Monika, 17: "In some ways I feel like an adult and in some ways I don't. I'm definitely in between."
There are two key words that seem to be crucial to the Western concept of adulthood: responsibility and independence. If you're a child, at least in the Western world, you are neither independent, nor are you expected to be responsible for others.
If you're an adult, you are expected to be financially independent, and to accept responsibility for yourself, your family and your community.
In the poorer countries of the developing world, on the other hand, it's rather different. In rural Ghana in West Africa, for example, I met a 14-year-old boy helping his uncle to catch fish. "I need the money," he said, "so I help my uncle. I use the money he gives me to buy things I need, like books or a pair of shoes. And I give some to the family as well, to help them."
Santosh, 11, in Delhi runs a special bank for street children
And in the Indian capital, Delhi, I met 11-year-old Santosh, who may well be the world's youngest bank manager. He helps to run a special bank for street children, offering a safe place for them to deposit the pennies they earn by selling trinkets out on the filthy bustling streets of Old Delhi. He's not an adult, but he's certainly capable of taking on adult responsibilities.
At puberty, our bodies change and we begin to feel - and look - more like adults. But in most countries, the law tells us we won't be regarded as adults until we're 18. And often we're expected to stay in full-time education even longer. No wonder teenagers are confused.
In some cultures, there are rituals to help teenagers bridge the gap between childhood and adulthood. In Ghana, among the Krobo people, we watched a dipo ceremony. Six village girls, some of them bare-breasted, were sitting nervously on plastic chairs to each side of the village chief, waiting for a ceremony that marks a sexual rite of passage.
Before she's undertaken dipo, no Krobo girl is allowed to be sexually active. After dipo, she's ready.
"It's preparing for marriage," the wife of the village chief told me. "We purify the body to be clean for marriage. We take them to the outskirts of the village and prepare them; we teach them in a secret way how to serve their husband."
In Ghana rituals to help teenagers bridge the gap between childhood and adulthood
But sex is a big problem, in Ghana as much as in New York or London. Krobo girls are having sex earlier, which means disgrace unless they've already gone through dipo.
The Ghanaian children's rights activist Susan Sabaa told us: "In the olden days it was a way to protect the young girl because it attracts some penalty if you are found to be pregnant without dipo. But now there's a kind of perversion in that it is done much earlier, and once you have undergone dipo, then anything goes. It gives you a licence to be sexually active, so it has defeated the entire concept of a transition to adulthood."
Our biological maturity, our social maturity and our sense of our own emotional maturity all happen out of synch - they certainly don't all happily click into place on our 18th birthday.
But what we've discovered is that young people can often demonstrate a remarkable capacity to act as adults, whatever their age. And sometimes, they're more grown up than grown ups themselves.
You can listen to this programme on the World Service at 0905 GMT on Monday 4 December.