After settling himself down perfectly well every night, recently my child has started getting the heebie jeebies about everything, including 'the creature in the roof', the 'thing outside the door', and the 'funny noises' (the sound of the cork coming out of my emergency wine).
Nothing seems to reassure him, and aged seven, we're back to the old days of staying in his room until he goes to sleep. Yawn.
But I know I was the same. Apart from a fearless few, as children we surely all lived in a state of constant alarm about monsters, ghosts and things that went bump in the night.
And sometimes the imagination, and the weird associations it makes, can conspire to create fear where there really shouldn't be any. When I was his age, I was scared of pine cones, for God's sake.
In a kid's life, fear is as common as nits and tantrums. After all, they've just come out of a cushy nine month womb rental where everything is warm, cosy and safe, so it's no wonder that the world can seem seriously weird.
It's a scary place - and some parents are required to go to serious lengths to allay their kid's fears. Take Jane for example: "When my daughter Lara was four, she became convinced that there was a 'Bad Teletubby' hiding in her curtains," she says.
"So I would beat the curtains with an egg whisk and then pretend to chuck Evil Teletubby out the window. This was a nightly ritual. The neighbours must have thought I was stark staring mad."
But it's not just monsters and spooky mutant Teletubbies that scare them out of their wits. When you're young, you can be afraid of anything. From the happy-go-lucky Pinkyponk to buttons, balloons and yes, even POTATOES - the most innocuous object can fill them with terror.
"My five year old, Oskar, is frightened of heights, loud noises, traffic, monsters, the dark, strangers, the concept of 'big school' and er...bouncy castles," says Ella.
"Our kid has a fear of soft furry things," adds father of one Erno. "The longer and softer the fur, the more disgusted she is."
"I thought my real parents had been eaten by wolves and the wolves were wearing my parents' skin for a whole year when I was six," says Mel, breezily.
But it's not just kids who are constantly petrified. We carry our childhood irrational fears into adulthood, too.
A quick survey of parents showed that most of us are still gibbering under the duvet, trying to hide from the evil clown/potato. A childhood fear is a potent beast, and even now, thinking of it sends a shiver down the spine...
"I'm scared of wet toilet paper," says Jolene.
"I was scared of a tree with no leaves - or proper branches. It was taller than all the others, looked practically black and had a big jaggy bird's nest at the top. Just looking at it made me cry," Carrie shudders.
TV was a generator of fear, too, but not just the usual suspects like Dr Who and the Day of the Triffids. The test card girl, the theme to Picture Box (remember that?) and the ITV closedown all gave you the willies.
"I was scared of Ena Sharples from Coronation Street," says Gary. "I used to have to go and stand in the hall when she came on, even though I couldn't reach the light switch."
Even psychologists aren't above giving into their childhood fears. Therapist Alex Buxton admits that: "I was terrified of the huge angry insect that lived in the bonnet of my Dad's car.
"Part of what I do as an adult is help kids get rid of irrational fears using gentle hypnosis and other techniques. The first thing is to always understand that to the child, those fears make more sense than anything.
"Personally, I was quite disappointed to find out my giant bug was only windscreen wipers. But hey – that what happens when you get to 33 years old."
Yes, underneath our careers and business suits and adult confidence, we're all terrified basket cases, still fleeing from our childhood traumas and the ghost of Ena Sharples.
But when I sit in the bedroom tonight, willing my child to go to sleep, it's worth remembering that some of our children's fears are actually very real, and very rational indeed. And as parents, we should proceed with the utmost caution.
"My son was petrified of Peter Mandelson," says Marina. "He'd seen a horrid cartoon of him in the paper and asked me 'Mummy, what's that? ' I just dismissed him with 'it's Peter Mandelson.' Years of terror."
Don't have nightmares...