One piece of parenting advice you should never give is how other people should discipline their children. Telling them that they should smack their child/ send them to bed/ yell at them is guaranteed to meet with a frosty response. Parents need to decide among themselves how they should best discipline their child; you're not the child's parent, so you have no say in the matter.

Every parent will have encountered the self-appointed expert who loudly proclaims their opinions on when a child should reach certain milestones. They'll tell you that when their little angel was the same age he had already submitted his PhD. Don't tell anyone that a child should be doing certain things by a certain age. Children are all different, and will learn to walk or develop a vocabulary in their own good time.

Even expert opinions differ on how long you should breast-feed a child for. Even if you think that a woman is breast-feeding a child that is far too old, keep quiet. It's not for you to decide when she should stop. A mother and her child will stop when the time is right for them.

Have you ever met the type of woman who pontificates about how having a Caesarian isn't really giving birth? Never give other women advice on their birth plan if they haven't asked for it. Giving birth is such a personal experience that other people's opinions shouldn't come into it. The only other opinion that counts is that of her obstetrician and midwife.

Most parents have heard this at some point. They've been told that having an only child is selfish, or that they can't afford a larger family. It seems that whatever people do is wrong! Nobody wants to hear opinions on how big their family should be, so keep your comments to yourself.

Vegetarian parents get a lot of criticism from others. But it's entirely up to the parents if they want to bring their child up on a vegetarian diet. This is perfectly healthy providing the parents ensure that the child gets all the nutrition they need from vegetarian sources. Also, don't tell anyone how that they should force their child to eat new foods or that giving them treats is harmful.

Many parents who give their children pacifiers will have seen and heard disapproving tuts from strangers, and comments like "it'll deform their teeth." Sometimes a pacifier is the only thing that will calm a fractious child, and you shouldn't judge parents if they decide to use them.

If other parents want advice on child-rearing, they will ask for it. Don't think that you know best, as it will definitely not go down well. You should particularly avoid giving complete strangers unwanted advice on how to bring up their kids. What's the most annoying piece of parenting advice someone's ever given you?