Try finding an actual teenager on a US television drama. Oh sure, there are lots of teenage characters but – and correct me if I’m wrong – most of them are sporting enormous bazookas, five o’clock shadows and zero acne. Teens on shows like Glee (which I love) don’t actually look anything like the high school kids that occasionally heckle me when I give high school writing workshops. And with good reason.

Glee’s Lea Michele is 24 playing 17-year-old Gleek, Rachel Berry. Her on-again, off-again par amour, Finn (Cory Monteith) turns 30 next year. That’s right. THIRTY. No wonder that show has so much angst – the cast are each in the midst of a quarter-life crisis. Not that Glee’s casting is rare, by any means. When Tom Wellings was cast as 15-year-old Clark Kent on Smallville, he was already the ripe old age of 24. I’m sorry but when Wellings was striding around Smallville High he looked less like a school kid and more like my optometrist. Then there’s actor Benjamin McKenzie who was 26 years-old when cast as the 16-year-old brooding Ryan on The OC. Charisma Carpenter was 29 when cast as 16-year-old Cordelia on Buffy. Scott Wolf was 26-year-old when he played 17-year-old Bailey Salinger on Party of Five.

Watch repeats of Beverley Hills 90210 and you’ll see Dylan McKay (Luke Perry) – one of the first teenagers I’ve seen with a receding hairline (Perry was 25 playing 18). And it’s a wonder 90210 didn’t do a “I wonder if I should freeze my eggs?” Very Special Episode featuring Andrea since actress Gabrielle Carteris was a spritely 34-years-old when she played the sixteen-year-old school nerd.

Cory Monteith from Glee is 29

And don’t for a second go thinking that ‘faux-teening’ is a new phenomenon. Whack Grease in your VCR and you’ll realise that Rydell High was more like an Adult Community College. When this movie about a group of high school kids was filmed in 1978, Olivia Newton John (Sandy) was 29, John Travolta (Danny) was a more youthful 24 but Stockard Channing was (like Carteris) a ridiculous 34-years-old when she played Rizzo.

So the question is, why aren’t genuine pimply, gangly, awkward teenagers being cast as teenagers? Answer: Because genuine teenagers are often pimply, gangly and awkward. That doesn’t look good on camera. Adults playing teens is commercially a better proposition to TV networks.

The upshot of this is that these highly articulate, zit-free TV ‘faux-teens’ (who all seem to pose for FHM in their spare time) leave real teenagers feeling insecure and inadequate.

Dr Karen Brooks, associate professor of Media Studies at Southern Cross University and all round pop-culture expert, agrees.

The cast of 90210

“Using adults to represent teens is another way in which so many popular culture forms accelerate maturation for the target audience and leave them with a sense that their own stage of life is somehow invalid and uninteresting. It can potentially instil in young people the desire to ‘grow up’ – especially through aesthetic means. Sadly, this can be readily achieved these days but while a young person in the ‘real’ world might look older, they don’t always have the cognitive skills to match, unlike their televisual counterparts – and that’s very problematic.”

So next time you and your teen are watching Gossip Girl or Glee, it might be an idea to subtly point out that in real life Finn is closer to your age than theirs. Which, when I think about it, works quite well for my single 30-something girlfriends.

Who is your favourite TV teen of all time?

Scott Wolf was 26 playing 17 year-old Bailey on Party Of Five

Luke Perry was 25 playing 18 year-old Dylan McKay in 90210

James Van Der Beek was 21 playing 17 year-old Dawson on Dawson's Creek

Gabrielle Cateris was 34 playing Andrea in Beverly Hills 90210

Blake Lively was 20 when she was cast in Gossip Girl as 17 year-old Serena.

Benjamin McKenzie was 26 when he was playing Ryan on The OC

Charisma Carpenter was 29 playing Cordelia on Buffy (set in a high school)

Lea Michele is 24 playing 17 year-old Rachel in Glee

Alex Dimitriades was 21 when he played 17 year-old Nick on Heartbreak High

Jason Priestly was 21 when he started playing 17 year-old Brandon Walsh (and stayed on for eight years).

Ian Ziering was 26 when he was cast as 17 year-old Steve Sanders in 90210

Callan Mulvey 21 was when playing 17 year-old Drazic on Heartbreak High

Dianna Agron is 25 playing 17 year-old Quinn in Glee.

John Travolta was 24 when he played high school teen Danny in Grease

Katie Holmes was 20 when she played 16 year-old Joey Potter on Dawson's Creek

Cory Monteith is 29 playing Finn in Glee

Chace Crawford was 22 when he started playing in 17 year-old Nate in Gossip Girl

Olivia Newton-John was 29 when she played high school teen Sandy in Grease

Joshua Jackson was 20 when he was cast as 17 year-old Pacey in Dawson's Creek

Tom Wellings was 24 when cast for the role of Clark Kent in Smallville.

Stockard Channing was 34 playing Rizzo in Grease.