The Duke and Duchess of Cambridge are about to have their first baby. There are plenty of things in short supply in this situation. Sleep, for example. But there is one thing that will come in unwelcomed abundance: advice.

Family, friends and more or less total strangers feel a compulsive urge to give advice. The royal couple will have extra advice from every attention-seeking pundit who can squeeze on to a television studio sofa.

Here are some of the worst forms of advice. Be warned.

1. Bossy books from bossy self-appointed experts.

Have new parents been robbed of their decision-making powers?

Why else would there be so many irritating books telling them how to behave. There are more than 70,000 parenting books on sale. They hide behind cutesy covers, all jelly colours and gurgling babies, but look within and it's more like a drill sergeant marching parents around the nursery.

Image caption Drill sergeant... or childcare expert?

These experts don't want to help young parents, they want to become leaders of cults. There are rules for everything and rule number one is that all the other rules are going to make everyone miserable. It's going to end in tears, usually from the parents.

2. Unbearably competent (borderline patronising) friends.

Make that ex-friends, because it's not normal to have life so well organised.

Six gurus of childcare History has provided no shortage of "supernanny" figures with big ideas about how best to raise children. Here are six of the people who have had the biggest impact on parenting over the past 100 years... Six childcare gurus who have changed parenting

You know the sort. He's baking organic vegetable snacks while she's teaching the two-year-old how to count in Catalan.

They organised the right school moments after conception. They know everything, you know nothing.

Their baby has never cried, never thrown up on the hire car, it never even really seemed to be a baby at all, but was more like a middle-aged Archers' fan hidden in a macrame shawl. And please, please, please don't tell us how to be like you.

3. My life is falling apart, but let me give you a few tips about yours.

Image caption OK, now I'm ready to give you some stellar advice...

You know the scene. A glass of white wine the size of Greenland has been poured, it's late in the evening, they're coming across the room to share some of their worldly wisdom, to pass on the secrets of their special way with relationships.

OK, their own children haven't talked to them in a decade, their family only communicates through solicitors and all their exes operate a postcode-wide exclusion zone… but none of this seems to deter them from thinking of themselves as relationship gurus, and unless you can organise a restraining order you're going to hear exactly what they think.

4. The undermining in-law.

Image caption Robert de Niro and Ben Stiller in Meet the Parents

Entering a minefield is probably an understated way of describing the emotional tripwires that new parenthood can bring to families.

No matter how delicately it's put, there is a high risk of advice from an in-law becoming a provocative intrusion.

There's an unspoken implication of a new parent not quite being up to the job. The touch paper has been lit, stand back and wait for the explosion.

5. They do it better in France.

Image caption Ice cream, fast food? Mais, non!

They've got a second home there, they drive down in the summer and they come back with that certain je ne sais quoi.

The quoi in question is usually along the lines of how much nicer French children's clothes are and how French children can eat in restaurants without looking like they've been face-painting with guacamole.

And they just can't resist giving you that little tip, that little special bit of advice picked up from an old French villager. Just learn how to say non.

6. I've read this thing on the internet.

Image caption Yes but he's very well read in child psychology

It was written by a crackpot who lives in a survivalist camp in Idaho with a greasy cap for a best friend and it has all the moral authority of a ransom note.

But it's this thing that everyone's reading on the internet.

Some blog, or a craze on YouTube, probably faked by a PR company, but hey, it's on a website that Rudy or Trudy recommended at the book club.

It must be true. Obviously. All you have to do is follow the instructions.

7. I hadn't realised that you had psychic powers.

Because how else could you know exactly what my child is thinking. "I think he wants his food," or "I think she wants to sit somewhere out of the sun."

You must have a secret knowledge hidden to all others.

8. The equipment bore.

There's a part of every man's soul that is taken up with extreme detail. You can see these new fathers in John Lewis applying their trainspotting skills to the buying of buggies, slings, cots, electronic toys and anything else that might involve a set of instructions.

And of course, what they know, they want to share. They want to give you the benefit of their expertise. You don't want to do it like that…

9. Dr Google will see you now.

Beware the amateur doctors, the DIY child development experts, who want to give their advice to you so freely and generously.

Any medical condition or developmental difficulty can be handed over to their in-depth skills.

After all who wouldn't want to give medical advice if they had watched a loosely-related TV documentary or seen most of a video forwarded by a friend on Facebook?

10. There is no such thing as new advice.

The first advice column was published in the 1690s. If they still haven't found out the right answers to everything by now there's probably not that much point worrying about it.

Is that reassuring advice?

Here is a selection of readers' advice for first-time parents.