We all want to look like the best version of ourselves: happy and fun, with great hair and no double chin.
That's why it's so tempting to use a picture that was taken sometime in the last millennium, a cartoon avatar - or a super-cute snap of your astonishingly photogenic child.
Yes, we've all done it - I certainly have. In lots of ways it makes sense - most of us use Facebook to keep in touch with friends and family who we don't see much in the real world, and it gives us a good opportunity to show off our gorgeous children.
If you've recently given birth, you're unlikely to be looking your best - by recently, I mean any point between labour and your kids starting nursery. And who wants to post a picture that clearly shows your tired eyes, unbrushed hair and growing collection of crow's feet?
But if you're tempted to hide behind a photograph of your perfect child, then think again.
We all know that there are weirdos out there who might try to build up a bit too much information about you and your nearest and dearest, but that's not the main reason why we should banish our kids from our profile pictures.
If your Facebook avatar doesn't show your face, then you're effectively surrendering your online identity at the time in your life when you're likely to rely on it more than ever.
When you have a baby, it's so easy to lose touch with your friends. If you're on maternity leave, it doesn't take long to feel disconnected from your old life - and if you're stuck at home day in-day out, social networks like Facebook can be a lifeline.
For some mums (and dads), Facebook is central to their social life - they can chat to their old friends, or join forums and make new ones. At their best, social networks can play an invaluable role in helping to tackle the loneliness and isolation that affects so many new parents.
As you adjust to being a parent, it's more important than ever to cling on to whatever aspects of your 'old' life still make you feel like 'you'. Nights out might be few and far between, but most of us can manage a few minutes on Facebook - which is why it's so crucial to maintain your own independent identity, rather than redefining yourself solely as someone's mum.
Using a picture of your baby not only makes it harder for old, or new, friends to find you - especially if you've married and changed your name - but it also has a habit of distancing you from friends who don't have children and miss chatting to you about last night's telly rather than sleepless nights and dirty nappies.
Substituting your picture with a photograph of your child suggests that you no longer think you are attractive or interesting enough to connect with other people. It's a slippery slope and once you lose your self confidence it's tough to get it back.
"When you have a new baby it's very easy to get subsumed by motherhood," says personal development coach and therapist Gladeana McMahon.
"This is a side-effect of developing another new identity. As well as being a wife, daughter, sister, friend and colleague you are adjusting to becoming a mother and it can take a while to make the transition.
"It's especially hard during the first few months if you've lost all your 'anchors', such as your job, daily routine or social life, as this can make you feel a little 'at sea'.
"Using your child's picture instead of your own sends out a strong message about how you feel about yourself - you're telling the world that you don't want to be seen and you're no longer important.
"Bear in mind that your friends will respond far better to a picture of you. By all means, post pictures of your family and allow your friends to share your happiness, but don't forget that your friends like you for being you, so don't hide away."
That's not so say that being a mum is anything to be ashamed of - quite the opposite. But there's so much opportunity to share photographs on Facebook that there's really no need to substitute the one picture that's meant to represent you with a picture of someone else. Even if that someone else is your much-loved child.
What do you think?
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