It turns out being breastfed or bottle fed can determine whether your baby will be right or left handed.

The debate over breastfeeding vs bottle feeding never seems to end, and frankly we think it’s a completely personal decision, but the choice you make could have an interesting consequence.  A recent University of Washington study discovered a link between the way a baby is fed and whether they turn out to be right or left handed.

Nature vs Nuture

Even though the hand you write with is largely affected by genetics, there is also an element of nurture in determining the final outcome. The study found that being left handed was more common amongst children who were not breastfed. “We think breastfeeding optimises the process the brain undergoes when solidifying handedness,” the study’s author Phillippe Hujoel said. “The critical age window for establishing hemispheric dominance in handedness includes the first nine months of infancy and is in part determined by nurture.” We have to say we’re a little sceptical.

Does It Matter?

The study acknowledges that the method of feeding may only have a minimal impact on the hand that a child eventually ends up writing with, with initial hand preference not always indicative of the final outcome. It also suggested that the length of time that a child is breastfed for is an important factor. “It provides an independent line of evidence that breastfeeding may need to last six to nine months,” Professor Hujoel said.

So does it really matter what hand your child writes with? And does the way you feed them really have any ability to alter their preference? Who knows, but we think most mums have other concerns when it comes to choosing the best option!

Do the findings of the study hold up in your family? Tell us in the comments!



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  • No way. My nieces were breastfed and they are left handers, my boys were bottle fed and they are also left handed. My granddaughters were all breastfed and they are all right handed. Frankly it doesn’t mean squat.


  • No. I BF both my children. My son is right handed & my daughter is Left..!


  • Surely this is coincidence. It doesn’t seem likely.


  • I don’t know I think this is silly, I breast fed & bottle fed both of mine for different periods and they are both right handed? Who cares which hand they write with though really?


  • I think this is ridiculous. My family (including extended family) has an even split of left and right handedness and also of breastfed or not and there is literally no correlation between the two.


  • Both of my children were bottle fed and both are right handed.


  • Well this study doesn’t hold up in my family. Only my dad was a southpaw and he was breastfed.


  • Haha so ridiculous. I was not breast fed and am right handed


  • Both of mine were breastfed and are both right handed


  • Guess one would have had to start investigating this right from the start when the baby was born. Long process.


  • I was always told to hold something in front of a baby and let them take it with the hand they are comfortable with and not to force them in any way with either hand


  • My Paediatrician was suspicious I was left handed before I was even holding the bottle on my own. I started later than some do as I had weak muscles and didn’t hold the bottle high enough and was sucking too much air. Mum hadn’t taken any notice which hand I took my rattle with. One day the Paediatrician asked Mum if she had a toy with her. It didn’t where he held or put my rattle I always took it in my left hand. He told Mum I was a definite “left hander” and I was not to be changed under any circumstance, that there was a possibility of brain problems. I eat left handed with a spoon but right handed with a knife and fork. That is logical. You put your fork in your mouth, not the fork. My brother and both my parents are right handed.


  • Correlation does not equal causation!


  • Both my children are lefties. They were exclusively breast fed for a few mths, mix fed and the on formula. My sister in law has 2 lefties, both of which were exclusively breast fed. My mum who was solely formula fed is the only other leftie in both families.


  • What a weird study

    • I agree, I don’t want to be rude but was thinking “what a bunch of nonsense” !


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