Ever since I became one myself, I’ve been uneasy about the clichéd way teenagers (aka young adults) are portrayed. I did a bit of research before beginning my latest YA novels and found a minefield of misunderstanding. There’s more myth about teenagers, I realised, than about the entire galaxy of ancient Greek gods and goddesses!

The task for my new series (so far The Soterion Mission and Revenge of the Zeds) was simple: challenge the teenage stereotype and set the record straight.

To do this, I set the books about a century after the 2017 Mini Flu epidemic. The seemingly harmless disease altered human DNA so no one lives beyond their 18th year. Following the Great Death, the world is run by teenagers. The distinction between teenager and adult has gone – teenagers are the adults.

And what’s this world like? Though their lives are technologically primitive, their behaviour is uncannily similar to our own. Surprised? Not if one remembers that ‘young adults’ are just what it says on the tin: adults.

MYTH: There have always been teenagers.

Of course there have always been people aged between 13 and 19. But the word ‘teen’ didn’t appear until 1899, and the use of ‘teenager’ was almost unheard of before the 1950s. But we love putting people into pigeon holes. As soon as ‘teenager’ had been invented, it was seized on by all kinds of 20+ experts – and we’ve been stuck with it ever since.

MYTH: Teenage behaviour is the same the world over.

True, young people tend to be more open, straightforward and impetuous than older ones. Does this mean all of them – or even the majority – behave the same way? Of course not.

Take two extreme examples: a middle-class American student, with little serious responsibility other than for their high school and college grades, and a Saudi Arabian Bedouin married at 14 and parent of three children by the age of 18. The lifestyles and attitudes of these two teenagers couldn’t be further apart. (Incidentally, in case you’re wondering, Saudi Arabia has no legal minimum age of consent / marriage.)

MYTH: Teenagers are irresponsible.

Oh yes? Like nearly everyone, teenagers behave as society expects them to behave.

Case Study: I left school at 18 and worked as a teacher. I dressed like a teacher, behaved like a teacher and, as far as I can remember, even thought like a teacher. A year later (and older) I became an undergraduate. I dressed like an undergraduate and – confession time! – (mis)behaved like an undergraduate. My age had nothing to do with my sense of responsibility.

And, by the way, the age of criminal responsibility in England is … 10!

MYTH: Being a teenager is ‘just a phase’.

We’re back at that pigeon-holing business again. Ever since Shakespeare made one of his characters divide human life into seven ages, so-called experts have been dreaming up categories to slot us into. The reality is that life’s a roller coaster – up and down, backwards and forwards, with everyone moving at different speeds. Never heard a boy called a ‘little old man’ or seen an adult behaving childishly?

‘Teenager’ may be a convenient label – but choosing an item by its label is no guarantee that it fits.

MYTH: Teenagers are selfish.

Teenagers are no more selfish than anyone else. If some do behave selfishly, it’s probably because they’re spoilt. And why does that happen? Because in our society everything is judged by its cash value. Children are their parents’ biggest investment: the cost of a child from birth to graduation is now reckoned to be £227,000 (Centre for Economic and Business Research, 2014). That makes two children more expensive than the house and car combined.

Because they cost so much, children are padded, protected, guarded and mollycoddled like Tudor princes. In his excellent book The Invention of Childhood (BBC, 2006), Professor Hugh Cunningham agrees. Spoiling does no one a service.

MYTH: Teenagers are promiscuous.

Three points here. One, surveys suggest young people are more critical of ‘cheating’ (ie moral) than older ones. Two, those who criticise teenage sexual behaviour often do so out of jealousy! Three, teenagers behave as society allows – eg the private lives of teenagers in Manchester don’t have much in common with those in Malaysia or Manchuria.

MYTH: Teenagers are a clearly defined group.

Rubbish. A 16-year-old wins a gold medal in the pool – she’s a ‘woman’. The same person is bullied at school – and calls ‘child’ line. They then beat up an old lady – and are now a ‘yoof’! At school or college they’re sometimes a ‘pupil’ and sometimes a ‘student’. In a bad mood they’re branded ‘adolescent’. And reading The Soterion Mission? A ‘young adult’, of course!

MYTH: Teenagers can’t be good parents.

Parenting skills depend on personality and upbringing. Older parents, having spent years thinking only of their own well-being, find it difficult to welcome a new and demanding individual into their lives. In the West today we frown on teenage parenthood. For most of human history this sort of thinking would have been seen as perverse.

Are we really any better than our ancestors?

MYTH: Teenagers don’t read books.

Wrong. Like adults, some do, some don’t. Ok, teenagers don’t like being told what to read – but who does? And yes, they’re tech-savvy enough to handle a wide range of media. But I know they still read books because they write to me (mostly kindly!) about mine!

MYTH: One can generalise meaningfully about teenagers.

This should be pretty obvious by now. The age at which people are thought ‘young’ changes over time and between cultures. And the way younger adults behave has also changed through history and according to community values.

But as we’re stuck with the word ‘teenager’, what do we do? We could use it in a non-judgemental way just to mean those aged 13-19. Or, better still, we could ditch it altogether and take people for what they are, not how they’re labelled.

So, that’s where my research took me. To see what I then did with it, check out the fascinating world of The Soterion Mission and The Revenge of the Zeds, where you’re adult at 11 – and dead by 19!

Do you have any other myths about teenagers you’d like to debunk, or examples of teenagers changing the world or challenging stereotypes? I’d love to hear from you on Twitter: @booksmyth