Picture a 21st-century ending for Jane Austen's classic novel, Pride And Prejudice. Instead of the Bennet sisters marrying the men of their dreams, they are reaching for another slug of whisky. They've learned the harsh realities of life.

And they hurt, most deeply. Because, girls, there's not a hope of living happily. Don't delude yourselves. These days you're more likely to find a unicorn than a Mr Darcy.

Though, if today's top fiction offerings for young people are anything to go by, you might well meet a Ms Darcy or an Elizabeth Bennet who swings both ways sexually and can't make up her mind.

Sarah Foot suggests today's young adult novels are full of gloom, doom, family breakdown and gender uncertainty and that there is not enough balance of light-hearted topics available for teenagers

Oh my poor nerves, as Mrs Bennet, her distraught mother, might say.

I first read Pride And Prejudice when I was 13, a girl hungry for romance. Dear reader, I loved it. It was a relief from worrying. About everything. Was I pretty enough? Was I clever enough? And, being the Seventies, did it matter because we were all going to be annihilated in a nuclear World War III anyway?

I needed somewhere to escape and in Jane Austen and in lots of other books I borrowed from the library, I found it.

But today's 13-year-olds are not fed such fairy tales. With a son of that age, I know it all too well. And it was confirmed when I saw the shortlist for the Waterstones book awards for teenage fiction.

The chosen few cover subjects that at that age I had never even heard of - parental child abuse, obscene bullying and crippling sexual confusion.

Top of the pile is a novel about a 14-year-old boy who wants to become a girl and is unable to tell his parents how he feels. This is closely followed by a story of a twin brother and sister who are devastated after their mother's death and then discover they both love boys.

Another is the tale of a mother who takes out a restraining order against her former partner.

Gloom, doom, family breakdown and gender uncertainty. All these are real and worthy subjects and I'm not suggesting children should be feather-bedded and kept away from them. But they are not the totality of life in the 21st century, yet that is the picture we seem to be presenting to the next generation. It's as if we've lost all sense of balance.

Take the seemingly unstoppable vogue for children's books centring on sexual identity, as this new list seems to exemplify.

It worries me, not because I'm intolerant. Each to his own. But I do wonder if it is we, as adults, who are the ones who are obsessed with it, hungry for a right-on subject to write about and show off how incredibly empathic we are.

As I scanned the school librarian's list, I was appalled. Here were tales of teenagers with intense suicidal thoughts. A dying mother. A father who'd gone missing.

It's hardly a mainstream issue. Clinicians believe that 1 per cent of us 'have transgender feelings to some extent'. But that means 99 per cent do not.

Only an estimated one in 125,000 is believed to have gender dysphoria - the conviction of being born in the wrong body, previously known as transsexualism - like David in Lisa Williamson's The Art Of Being Normal, one of the books on the short list.

Of course, if novels such as this help improve understanding and reduce prejudice, that's wonderful. If it makes one person feel less alone, that's to be embraced.

But this fashion makes for such a narrow range of reading. It's not just those questioning their sexual identity who know what it is to struggle.

And there is a much bigger issue with teenage literature than obsessions with essentially niches. The truth is that so much of it is desperately bleak.

A friend sent me a list of books recommended for 12 and 13-year-olds by the librarian of one of London's leading prep schools.

'Something light' was what I had in mind for my son. A book that is an escape from all the fear and rage of adolescence. A story that showed life can be happy, that there is joy as well as tears.

I suppose I was after the literary equivalent of the American TV series Friends which - though it never ducks complex social problems such as divorce, gay parents, IVF and so on - makes my son and his friends roar with laughter.

But as I scanned the school librarian's list, I was appalled. Here were tales of teenagers with intense suicidal thoughts. A dying mother. A father who'd gone missing. A psychiatric clinic deploying unorthodox therapies on vulnerable adolescents. Hideous bullying that ends in murder.

Mention any of these subjects to me and I'm likely to have an anxiety attack. Nevertheless, I ordered several of the novels and sat down to read, reminding myself these were for young adolescents and I'm in my 50s with all too many hard life experiences behind me.

It was not a cosy afternoon. Don't get me wrong. Some were works of art - great writing, all too believable characterisation, gripping plots. But most were so dark, so depressing.

Sarah was left reeling after finishing Emily Lochart's We Were Liars, an award-winning 'young adult' book about a teenage girl, from a troubled family

There was the tragedy of a teenager having cancer made utterly real when a 15-year-old is diagnosed with leukaemia and 'life shows you how very bad it can be'. And a story of a father returning from war and being 'close to a breakdown, lost in a world of imaginary threats'.

I was left reeling after finishing Emily Lochart's We Were Liars, an award-winning 'young adult' book about a teenage girl, from a troubled family, who suffers amnesia after a mysterious trauma. It's described as 'blisteringly smart'. And it is. But after 225 pages, it ends with: 'I endure.'

I endure? Is that all? As an adult you do learn that you endure, but you also learn that there are other things in life as well. Good things, such as love, hope, even just a kind word.

And I am left wondering if we are in serious danger of cutting our children off from that more positive side of life.

As I bemoaned the bleakness of the reading matter, my son explained it to me: 'You see, dark's the new thing.'

Certainly, Waterstones' children's book buyer Florentyna Martin said of her shortlist that it proves 'today's children do not just enjoy books for the escapism they offer, but for how they can illuminate life in all its shades of light and dark'.

I fear, however, that it's the darkness that is dominating.

Perhaps the reasoning is that today's youngsters are the most pampered generation in history - that they need to be reminded that not everyone lives as comfortably as they do, with all their gadgets and social media.

And yet I can't help thinking our children need as much relief from the world as I did 40 years ago.

When I look at my son's contemporaries, too many have already known dreadful loss and the most basic of human terrors: worrying about the death of those you love, being bullied or being an outsider. They don't need fiction to reveal this to them.

And when didn't life look dark to a troubled adolescent?

'The other thing,' my 12-year-old said, 'is dark's easier to write.' That's true. And how we writers can then flatter ourselves: how clever we are to recreate the minds of teenagers! How well we capture the troubling drama of growing up! Yet surely this is a ham-fisted way of dealing with adolescents?

On finishing We Were Liars, I asked myself if I could have behaved as terribly as one of its teenage characters - I won't give the plot away, but so terribly that I ended up ruining other people's lives?

Yes, quite possibly, I concluded. Literature had done its job - it had made me think.

But I'm an adult. I wonder how many teenagers have the emotional skills to handle such dreadful questions.

Of course, it can be a comfort to know you are not alone in feeling weird and scared. That sense of connection is one of the great beauties of literature. But I wish there was more of a middle ground in today's novels.

I think back on my own reading at this age. There was the horror of Lord Of The Flies, child cruelty in Oliver Twist.

However, there was plenty to leaven it. I raced through Georgette Heyer's romantic Regency novels, imagining, if only for an afternoon, that I was pretty and clever enough and there was no danger of a nuclear bomb dropping. I laughed out loud reading Gerald Durrell's My Family And Other Animals.

And best of all, of course, was Jane Austen.

I still turn to her now. She gives me a sense of hope - not that I'm going to meet Mr Darcy one day, but because of the joy that can be found in the complexity and drama of very ordinary lives.

And I wonder how many of today's teenagers will return to modern 'young adult' novels. Not many, I suspect.