• Christine

Is thumb-sucking and ‘handedness’ hereditary?


We have had a super exciting few weeks on the baby front. At around 19 weeks, lying in bed one night I finally felt a little ‘tap, tap, tapping’ and realised that it is our baby introducing itself. This wonderful sensation gets a little stronger every day and I can’t wait for my partner to be able to see and feel these kicks too.

Thankfully, I have stopped feeling sick now and am back to eating all of my favourite foods with gusto (apart from the forbidden fruits – how I miss a glass of wine and a good strong coffee!)


We just had our 20-week scan and were amazed to see our baby once again avidly sucking its thumb. In fact, the sonographer asked us to have a walk around for 20 minutes because despite a bit of poking, baby refused to take its thumb out of its mouth so that she could perform the measurements.

Once it obliged we were reassured that everything looks perfect with the baby so far, so we can now relax and enjoy the rest of our pregnancy journey.


Seeing our beautiful little thumb sucking baby (it was also sucking its thumb when we had a scan at 15 weeks) made me wonder if thumb sucking is hereditary? Both of my two brothers and myself were thumb suckers – apparently, we automatically put our thumbs into our mouths the moment we popped out, so it was obviously an art we had all perfected in the womb. My mum tells me that with my youngest brother, she tried giving him a dummy for a month to break the habit – but the moment she took it out of his mouth, the thumb popped in.


I have read that whichever thumb a baby sucks usually indicates its handedness – so if it sucks its right thumb it will generally be right-handed, and if it sucks the left, it will be left-handed. Our baby has been sucking its left thumb (in every scan the same hand) so we are now interested to see if this is true. My partner is left-handed, so the baby has potentially already picked up a trait from each of us!

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