Can Two Rights Make a Left?

Thursday, June 11, 2015

Time will tell, I suppose.  Doesn't every parent wonder at some point whether their wee one will become a righty or a lefty?  I sure do.  Lexi primarily sucks her right hand, but she will occasionally suck her left thumb too.  She picks up toys and food pretty equally with both hands at this point.  



Our pediatrician agrees that it's still too soon to know with Lexi.  However both John and I are righties so we have always tended to assume she will be too.   But in both cases, we both have moms who are/were lefties as well as siblings who are lefties too.  So I suppose there is a family connection somewhere in there too. 

With all that in mind, I decided to do a little research to see what the experts say.  It is actually pretty interesting, in that handedness is in fact genetic.  However, it's not as simple as right handedness being dominant and left handedness being recessive.  If that were the case, then two left handed parents would always make a left handed child, and two right handed parents would never make a left handed child, but as it happens, neither is the case.  

It turns out that in our case, two right handed parents still have a 1 in 10 chance of having a left handed child.  The same holds true if only the dad is left handed.  The odds rise to 2 in 10 if the mom is left handed, and 4 in 10 if both parents are left handed.  Clearly there is something other than genetics at work here.  If you look at identical twins, they start with the same DNA, however when one twin is a lefty, the other is also a lefty only 76% of the time.  Hmmm, very interesting. 

Experts believe that environment also plays a key role. Babies can be born genetically predispositioned to become a lefty but ultimately something needs to trigger it for that to happen. There is also some research to suggest that birth order plays a part as well.  That research indicated that first borns were less likely to become lefties than children who were born later in the birth order. In both our cases, that held true.  Misty is our lefty and she is the youngest of the three Harris sisters. In my husband's family, he is the first born and is a righty, but his younger brother is the lefty of their bunch. 

In many ways, I think it sure would be cool for Lexi to be a lefty.  But I also think it would be harder on us as parents to try to teach her to do things if she did them opposite from us.  Either way, she will be perfect.  And as I say, time will tell.  Until then it sure is fun to try to figure it all out.  :)


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