That's the monster we create by defending him or her in squabbles, letting off chores and generally treating as just that little bit special.
One example - or should that be indictment - my eldest does the ironing for some extra pocket money, my youngest mops the kitchen floor. One job takes at least an hour the other fifteen minutes and that's if it's done properly – which, by the way, it rarely is. Not an even a workload is it?
But it's not a conscious thing. I don't think eldest 3/10, youngest 9/10, therefore he gets the easy job, I just don't think!
But along with safety we can always take comfort in numbers, it isn't just me who inadvertently
favours my youngest. A survey of 1800 mums and dads carried out by Bounty showed that 60% of the time parents side with the younger rather than the elder child. And not only that, they are also more likely to lavish them with attention and let them have their own way.
Clinical psychologist Dr Rachel Andrews believes that parents can spoil their youngest child for a
number of reasons. "For parents who know the child will be their last, their motivation is often to make the most of having a young child.
"This can lead to them subconsciously wanting to keep their child 'little' by doing everything for them. A cycle can start where the youngest takes on the role of 'the baby' and a level of self-centred, irresponsible behaviour can inadvertently develop."
And don't we just create the problem of youngest child syndrome for ourselves! When, or if, we eventually wise up and start rethinking our parenting the object of our revised child development programme may sulk for days because they're not used to be asked to do things and will object to helping out with chores they'd previously managed to avoid – and who can blame them?
Food is another issue where discrimination appears to commonly occur. My friend Mary is mother to six children aged between 19 and 11. I strongly believe that anyone who can bring up six
well balanced, bright children is beyond criticism at any level however even Mary admits that she has been known to 'spoil' her youngest.
"Joanna, my eldest, recently reminded me of the time when she was made to sit in front of a plate of leftover onions until she'd eaten them. Ten years on Jonathan, my youngest, often gets away with leaving parts of his meal that he doesn't like.
"But I did Joanna a favour by being strict with her; she'll eat anything now whereas Jonathan will go through life refusing to eat bread crusts and picking mushrooms out of his meals."
With your first child, you are under the illusion that you can do everything right for them, whether it is only feeding them home cooked, home pureed food, ensuring they only watch organic television on rare occasions and religiously making time to sit down for story time – all of which are good but the second child comes along and you have less time.
Of course you still endeavour to get at least the big things right but the time you have for individual attention is halved. The third and subsequent children come along and the maths is the same - you have less and less time and it becomes natural to spend this limited time on your youngest because you feel they need you.
It's when this becomes a habit and continues way past the stage of them needing you anymore that you create a problem and, potentially, cause friction between siblings.
When my eldest was the age my youngest is now she was expected to be able to find her coat and shoes and be ready to go out without being told umpteen times.
My youngest is rarely capable of this - most likely because I perpetuate his 'hopelessness' by doing it for him whilst being given the 'evils' by my eldest.
But it's easier to find his coat and shoes than watch a 'should be capable not so small person' running around frantically looking in all the wrong places.
So it's probably a combination of different things including being worn out, worn down and just wanting to make life easy.
"Jonathan definitely got his own way more than the others," says Mary. "When his brothers and sisters went off to school I would often let him watch DVD's as it meant I could sit down and put my feet up."
Well whatever the underlying reason or thought process that led to that decision, if anyone was
entitled to do that I think it was probably Mary with her six children.
More on Parentdish: Second child syndrome
Figuring Out Fatherhood: The difference between first and second children