Visit our online shop for your left-handed productsWhat is the chance of having a left handed child?
This article was written by Keith Milsom, owner of Anything Left-Handed, in response to lots of questions from Left Handers Club members.
About 10% of the world’s population are left-handed and it seems that left-handedness runs in families, with the handedness of the mother being an important factor. So what are the chances of having a left-handed child?
Various studies have shown that around 10% of the world’s population are naturally left-handed and that this seems to be a fairly consistent figure over a long period of time and in all countries and cultures. The way left-handedness is measured and the fact that many cultures deliberately suppress left-handedness complicate the picture, but left-handedness seems to stay at about that level anyway. More recent studies among children show a higher level, may be increasing.
It also seems to run in families, although no gene for left-handedness has been isolated and it is not possible to predict left-handedness in the same way as, say, eye colour. What we do know is that the more left-handers you have in the family, the more chance of having left-handed children. The probabilities of various left-right parent combinations having a left-handed child vary quite a lot depending on which research you look at.
Dr Chris McManus reported in his book Right Hand, Left Hand on a study he had done based on a review of scientific literature which showed parent handedness for 70,000 children. On average, the chances of two right-handed parents having a left-handed child were around 9% left-handed children, two left-handed parents around 26% and one left and one right-handed parent around 19%.
In The Left-Handers Handbook, Diane Paul repeated this and also noted that Left-handed mothers are more likely to have left-handed children than left-handed fathers. This was based on research done by Stanley Coren for his book The Left Hander Syndrome, where he showed the chances of two right-handed parents having a left-handed child were around 10%, a right-handed mother and left-handed father the same, 10%, left-handed mother and right-handed father 20% and two left-handed parents 35%.
A large survey carried out by Anything Left-Handed showed that only 1.4% of left-handers who responded had two left-handed parent, 24% had one left-handed parent and 75% had two right-handed parents.
Are all these numbers consistent with each other?
If those percentages are true, would the level of left-handedness in the population as a whole stay at a consistent level?
I have produced a model that calculates the mix of handedness in parents and then multiples by the assumed probabilities for each mix having left-handed children to calculate the total number of left-handed children and their percentage of the population. For example, if 10% of the population is left-handed, only 1% of all couples will be made up of two left-handers (like me an my wife, but there is a theory that left-handers attract each other which would distort this, but that is for another article!).
Putting Chris McManus’s percentages into the model shows an increase from 10% to 11.5% in the level of left-handedness in the population in one generation and if that continued for very long left-handers would no longer be in the minority! Stanley Coren’s figures, although quite different, also give an increase in left-handedness to 11.2% and neither of them give a match to the figures from the Anything Left-Handed survey. Most significantly, the number of left-handed children with two left-handed parents is 2.3% for McManus and 3.1% for Coren. To get down to the level of only 1.4% found in the Anything Left-Handed survey, the chances of two left-handed parents having a left-handed child need to be reduced to around 14% – much closer to the other parent mixes.
Juggling the figures to get the best match to all these results, plus also keeping the level of left-handedness stable at around 10%, these probabilities of having a left-handed child seem to fit:
Two right handed parents, 9%
Left handed father, 12%
Left handed mother, 16%
Two left handed parents, 20%
There are many more variables that affect these figures and one study showed that left-handers have less children on average that right handers. This is meant to be a guide rather than a scientific conclusion.
However, whichever set of assumptions you use, some interesting figures come out:
- More than 50% of left-handers do not know of any other left-hander anywhere in their living family.
- Around 75% of left-handers have two right-handed parents and only 2% have two left-handed parents.
- Between 7 and 8 out of 10 children born to two left handed parents will be right handed.
Of course, the chances of having a left-hander in the family increase the more children you have. So there is still hope for right-handed parents – if you have enough children, you may still be lucky enough to have a left-hander!
Keith’s model of left-handedness
This is my Excel sheet used for calculating left-handed probabilities. I must state again that this is only a layman’s analysis – if there are any statisticians out there who can improve on this please let me know.
Click here to download the actual Excel workbook if you would like to play with the numbers yourself
| WHAT IS THE CHANCE OF HAVING A LEFT-HANDED CHILD? | |||||||||
| Starting number of individuals | 1,000,000 | ||||||||
| Starting number of couples | 500,000 | ||||||||
| Assumed starting rate of left-handedness in the population | 10% | ||||||||
| Percentage chances of having a left-handed child for each possible parent combination | |||||||||
Percent of |
% chance |
% of LH |
% of RH |
||||||
all couples |
Number of |
of LH |
Number of |
children |
Number of |
children |
Total |
||
| Father | Mother | with mix |
Couples |
child |
LH children |
with mix |
RH children |
with mix |
Children |
| Left | Left | 1% | 5,000 | 20.0% | 1,000 | 2.0% | 4,000 | 0.9% | 5,000 |
| Left | Right | 9% | 45,000 | 12.0% | 5,400 | 10.8% | 39,600 | 8.8% | 45,000 |
| Right | Left | 9% | 45,000 | 16.0% | 7,200 | 14.4% | 37,800 | 8.4% | 45,000 |
| Right | Right | 81% | 405,000 | 9.0% | 36,450 | 72.8% | 368,550 | 81.9% | 405,000 |
| Total | 100% | 500,000 | 50,050 | 100.0% | 449,950 | 100.0% | 500,000 | ||
| Resulting percentage of left-handed children | 10.0% | ||||||||
| Percentage of all children born to two right-handed parents who are left-handed | 9.0% | ||||||||
Print This Page
My sister and I are both left-handed. We are the only people in our family who are left-handed. Our parents are both right-handed so i think it came quite a shock to them to find they had two left-handed kids. I play hockey right-handed because it is a right-handed sport but I do struggle a lot and i would feel a lot more confident using my left hand. I eat like a left-hander and so does my father even though he is a right-hander. For me it is a mystery. I just feel very special to be left handed as i was the only person in my class in school to be left-handed. It really does make you feel like you have something that nobody else around you has! from Emily
Could it be that your father is a latent lefty and was dicouraged from this when still very young. This is a very common practise
My both parents are right handed. We are 3 brothers & 2 sisters. Out of 3 , me & my younger brother are left handed. My wife is right handed and we have 2 sons ( twins) , one them is left handed. How in twins children one is right handed & one left handed. ?
About 25% of identical twins are mirror image twins, but I’m not sure why!
reason -one is sensible and good (RH) and the other mixed up good ‘n proper
My sister & I are both right handed (are husbands as well). 2 out of my sisters 3 children are left handed (the 2 youngest – boy & girl). I have 1 child (girl) & she is left handed as well. Is any of this connected & what are the odds of this hapening.
I fogot to mention that our father was left handed as well as his half sister & his mother.
I am a left-handed female, which obviously isn’t very common. But here’s something weird: my father is 1 of 14 children. 12 are surviving. 6 are males and 6 are females. 3 males are lefty and 3 females are lefty.
How about 2 right handed parents having 3 children who are all showing left handed tendencies? Two of them its for certain, and the youngest it’s looking that way.
I find this subject endlessly fascinating. I know my maternal grandmother was left-handed, however, both my parents are right-handed. I am personally delighted to say that it looks as though my little nephew is leaning left when he picks up toys or tries to feed himself, so perhaps I will have a little left handed buddy.
What’s strange about my husband and my’s situation is that he and his two brothers all married women that were left-handed! We’re all dead weight at mealtime at the parents’ home, between the peelers, knives, and the dreaded tin opener. My husband is American and my father-in-law told me he’d better get at least one good ’southpaw’ baseball pitcher from the three of us daughters-in-laws! (Evidently, they have an advantage!)
I have read all sorts of reasons as to why a person is left-handed, one being that very, very early on in development, we lefties had a twin that was reabsorbed. The thinking behind this is that of mirror twins, where, depending on which way each fetus is facing, one will be left-handed and one will be right-handed.
W.K. Koskei: That’s the very thing that my grandmother’s school did to her! It didn’t work, just as your teacher’s attempts didn’t, although I know some people who do everything left and yet they write with the right.
My hubby and I are both lefties….he basically writes left handed and that is about it. I play hockey which is a right handed sport of course and seem to do most other sports rh but have no problem switching to my left in tennis or squash if I get tired (much to PE teachers disgust when he tried to grade me in highschool lol). I throw with more distance with my right but far more accurate with my left. I eat with a knife and fork like a rh but with a spoon like a lh…cut with a knife with whatever hands feels comfortable at the time. I use a computer (inclusing mouse) like a rh person but was forced as a child to cut with scissors with my rh and to this day can’t cut straight to save myself. When I write I don’t have the distinctive lh curl which looks so uncomfortable. We have 3 boys…the first 2 are definate righties and my 3rd seems to be showing tendancies to be a leftie finally…but we will see
I just assumed that we would have lefties but they sure showed me.
For the record neither of our parents or siblings are left handed…mum remembers twin cousin/s possibly being but hubby has no recollection of anyone (but honestly that doesn’t mean anthing lol)…
My family is all right handed except for me, my aunt, and some great-cousins.
I am left handed and both my parents and both sets of grand parents, I don’t know about greats thought. As far as I know, only my half brother(Dads side) and possibly my cousin(also Dads side) are left handed. As to the best 10% of population(lefties) being more creative, I’ll provide this info: I am very musical, I play keyboard/piano clarinet and recorder and like to think I can sing, also I am a budding author, so I think we may be more creative. Who knows? Isn’t the left Sideof the brain the creatve side?
“It is said that the first right brain function is controlling the left side of the body. Right brained people generally tend to work more with their left hand and instinctively move their left foot forward first, while walking.”
Right brain dominance: “This brain dominance makes left-handers more likely than right handers to be creative and visual thinkers. This is supported by higher percentages of left-handers than normal in certain jobs and professions – music and the arts, media in general.”
Both my husband and I are right-handed and both our children (one boy and one girl) are left-handed. Now what’s the liklihood of that?
I am totally left handed (LH) but, like many lefties, can do lots of things right handed (RH) if I really want to! All grandparents were RH, all aunts and uncles were RH, all cousins RH, both parents RH and 2 brothers RH. The only LH I know of in the older generations is one of my father’s aunts. Others may have been forced to change of course, as was the custom in previous generations.
One of my 2 brothers has 3 RH sons and the other brother has 2 LH children and 1 RH. He blames me! My husband is RH and doesn’t know of any LHs up his family tree. My eldest child writes RH but plays most sports (tennis, squash, golf, soccer) LH or left footed, although he bowls a cricket ball with his RH. My 2 daughters are RH. I am eagerly awaiting the arrival of my first grandchild in May and hoping he/she will be a Lefty!
My husband and I are both lefties. We have a right handed son and a left handed daughter. Before me the only leftie in my family was my father’s uncle, his Mom’s brother. My Husbands Mom was right handed and his dad was left handed. The first girl is a leftie, Then a rightie girl, then a rightie son and lastly my husband a leftie. All of my cousins are rightie and most of them has at least on leftie child. My right handed sister and her right handed husband have 2 lefties and two righties.
Every time I watch the Gilmore Girls, that girl Paris Geller is also left-handed.
Oh, I forgot to mention that my father does the left thumb over the right upon clasping his hands together and so do I. My mother, older brother and younger brother do the right thumb over the left thumb. My father is really creative. Although we are all right handed people, I suspect being Asian has a lot to do with why we are not left handed. When I inquired my Mother about my hand preference as a child she was offended and defensively stated that “you were always a righted handed person!”. She explained that we were brought up to be well mannered right handed people. My Mother was also a Catholic so that was another cross to bear…left hand of the devil!
I injured my right shoulder and back when I was about 20 years old. It was so injured that I had to train my left hand to take over most of my right handed task which up until that point was virtually all my task. Doing so made me quite curious about handedness that I read two lengthy books on the left hand so that I could have a better idea of what it is all about in terms of the outward signs of the right brain dominant person. Is you left thumb on top if you clasp your hands together? Is your left arm on top when you cross your arms? Such are the outward displays of some left handedness. Turns out I can play tennis as a left handed person with less precision but greater creativity of shot selection. It is almost like two different people playing when I play as a right handed person as oppose to the left handed person. I’ve been reading the research and it looks like it’s a very good thing to do more activities with the left side as more creativity is released. I’m now 45 years old and I want to be more creative so anything left handed will be good to go do….keep to the LEFT>
My husband is left-handed, our daughter and her husband are right handed, and all her 3 children (2 boys then 1 girl) are all left-handed. We googled this site because we felt it was very rare and we were curious about the odds of it happening. We are please to see that it may be rare but not unheard of.
Does anyone know if left-handedness displays any signs of increased intelligence?
Naturally we feel our grand-children are brilliant but of course we are probably a bit biased.
Am W.k.koskei in Africa (Kenya) and am the only one in my family who is left-handed, in my father’s family tree, there was no one who was left-handed, ,however my mother’s family tree was, and that was my grand mother, and when i was 5yr old my mother took me to my grand maa and she use to discourage me a lot, they use to tie my hand so that i can use my right hand, however it never worked and today am 40yrs with my family and non of my 5 kids is left-handed, i would have loved if i had one!
Am grateful for having got a club of our own!
I am left handed along with my mother and sister. Apart from us, there is no known history of anyone being left handed in the family. My husband is right handed and we are currently expecting our first child, will be interesting to see if shes another lefty.
When I was at college there was 7 of us in a business studies class. All left handed. Weird!
My son is left handed. My twin sister (fraternal) was left handed until, in pre-school, they forced her to be right handed. I am right handed, my husband is right handed. My father’s cousins, who were also twins (identical), one was right handed, one was left handed. My father’s father was left handed. My daughter is right handed, but does have left handed tendencies as she will do certain things with her left hand before thinking about it and switching to her right.
I think its hit or miss, but I knew from the day we brought my son home after birth that he was going to be left handed. He favored that side very strongly when sleeping, always used that hand first for anything.
I’m proud of my lefty. It makes him more unique and special.
Me and my partner are both right handed. We have a set of identical twins, one is right-handed, the other left handed. Our 3rd daughter is also right handed.
Our little ‘lefty’ feels very left out (excuse the pun!) But my grandad and best friend are both left handed so she does have a lefty buddy who are just as special as she is!
I’m intrigued by these stats,
My Dad is right handed, Mum left. my brother, sister and me are all are left handed.
My wife is right handed. both my daughters are left handed
I think we have a super left gene
Hubby and I are left handed. We have 4 left handed & 1 right handed children plus youngest who is also ambi (was lefty at Nursery then started all again using right hand at Juniors but can write equally well with either hand)
I worked for a while at a special needs school and found out that left handed children had been fed right handed by right handed carers (badly) and when others couldn’t cut with left handed scissors it was put down to their being a lefty – turned out the scissors didn’t work. We need a minority group to stand up for leftys I had to work right handed in the Post office for a year until I left! Leftys need rights, or should I say lefts.
P.S wouldn’t be without my lefty tin opener, rehung fridge door and kids squeezy mouse (for computer).
shamepies ’bout te RH brat. what is ambi. in yer dreams mate. LOL
My Mother and Father were both right handed.They had three children.All three daughters are left handed.I am one of the left handed daughters my husband is right handed.We have three children all right handed and four grandchildren all right handed.
My next sister had a right handed husband and only child a daughter is left handed Do not know about grands and greatgrands.My oldest sister and her husband are left handed.Two of their four children are left handed.I do not know about grands and great- grands.
I find it interesting that my two grandsons are NOT left handed – I am, their father is, their mother is and maternal grandfather is left handed. That’s a lot of left handed influence. I know that it’s not supposed to be genetic, so what is it?
I was born to right handed parents, but all the girls in my family (both my 2 sisters) plus my own 2 daughters are total leftys. Having it reconised is fantastic by ‘Anything Left Handed’ because we can buy things that make life easier. Best gadget so far has been the bread knives as we can cut equal thickness slices of bread now instead of mishapen door wedges! Brill!
I think we may be a stastical anomoly – out of 8 cousins, 5 are left handed and 3 right-handed. We parents are 7:1 right to left-handed!
My parents are both right handed, as are both sets of grandparents…the only lefties that I know of in my family are my dad’s sister and her son…and I think my paternal great-great-uncle was left handed too…
And about left handers attracting each other – my boyfriend’s left handed (we’ve been dating for over 2 years but have known each other since we were 4)…and the first friend I made in playschool is left handed (and we’re still in touch now)…
It’s fantastic.My wife is also a leftie so our house is well set up for us..The kettle,the toaster etc..1 of our four children is left handed.Although they all kick a ball right footed and play racket sports right handed..
They do swim left handed though!! LOL..a wee joke for our poor rightie friends,like my RIGHT handed drum sticks!!!
I am left-handed, both of my children are left handed. My husband is right handed.
My parents are right handed.
One connection between three generations is that we are all very creative either through art or music!
My left handed son (age 9) taught himself to play the guitar right handed….and prefers it this way.
I am left handed from 2 right handed parents – I have one daughter who is also left handed and one right handed – my husband is right handed
I do voluntary work with two other ladies and all three of us are left handed !!
I started right handed, and I’ve been that way my whole life but I don’t know what happened this summer but now it’s almost impossible to write with my right hand and I have more controll over my left! I do have attention (never dianossed as add or adhd, sorry for spelling) but I don’t think that that would happen because of it? anyways no one else that I know of in my family is left handed so I feel… different now. A good different.
Annie, all of us are born right-handed, only the greatest among us overcome it. It sounds like you just overcame it later in life than most. Congratulations on your perseverance!
recently I discovered that my baby of one year is lift handed, he became the 3ed lift handed in my family
I’m a left-handed daughter of a left-handed Dad, and a right-handed Mum with a left handed sister. I have three right-handed daughters, which surprised me a bit, as their right-handed father came from a left-handed family. Thought there’d be at least one lefty in the mix. Guess I’ll have to see what happens with the grandkids when and if they arrive.
I have three children and all three kids ( 2boys, 1 girl) are all left handed. I’m right my parents are right and there dad is right. WEIRD!!!!!
My grandfather on my dad’s side was left handed and so am I! No one else in my family is left handed (except my older sisters husband). I hope their 3 wk old baby boy is left-handed.
We’ll so far I’m the only left handed female in my family but there are a few lefties; my grandfather, father & a male cousin and I have to say I like being ‘different’ and being left handed… I always tell people that left handed people are the top 10% of the population
My mom, my sister, and I are all left handed in a family of six. I know that two of my nephews are left handed…seems to be alot in one family.
OK, so does anyone else have three , yes all three of my children are left handed!! What are the odds of that???? And neither my husband nor I are! I know of no one alive on my immediate side of the family that is left handed and my husband, knows of one left handed uncle. We wondered if my kids just imitated their siblings and did what they saw?? Who knows. But there it is. They do do some things right handed. Like we know my eldest plays sports right handed!
Hi, I am like you.
My husband and I are right handed. My first son whose father died was right handed.
My other two children are also left handed. Like you, I don’t know anyone in any of the families who are left handed but all 3 of my children are left handed.
Hi Valerie,
I was just speaking with my sister today on this very subject after seeing a picture she sent of her youngest daughter via email. She was coloring, and I noticed she was holding the crayon in her left hand. I couldn’t believe it because her 2 older children are also lefties! This one is 2 1/2, but she has a sister who is 5 and a brother 6 1/2. My sister and her husband are both right handed. I am the only person my sister knows of anywhere in both of their families that is left handed. I have 3 little ones of my own and they are all right handed. She and I were just talking about how rare it must be, and here I googled a little bit and came upon your story. Thanks!
Proud Aunt Stephanie
my 7 year old son’s lefthanded, my sister in law and my father in law are also left handed.
My Grandmother was left handed, my Mum is left handed, I’m left handed, my Niece is left handed, and I’m waiting to see what my 2yr old daughter will be, she’s not showing any sign of a dominant side yet. A female pattern in my Family then…
My Grandfather is a lefty the only one in my family until my son came along. I think it’s hit or miss.
I have always told my wife that I am a genius, thank god for your website, now I have it in writing! Unfortunately, she still thinks I’m an idiot. (She is right handed)
in my family, its fairly random – me, my dad, then my youngest male cousin on my mums side and my step grandmother. Is this mostly chance? or something more ’sinister’ *mwa ha ha ha ha…*
Is lifthandness affect the way of one’s thinking or critiria of appreciating or assess such issues?
Must have been a recessive gene in my family. all four grandparents were right handed, my parents, aunts, uncles, cousins, brothers, and great grandparents were all right handed! I am the only living left handed person in my family. I dont know if my great great grandparents were or not, though.
My father was left handed, my mother right handed..
my elder sister and are both left handed…
our 2 younger brothes are both right handed…
Odd ? Pat.
no one of my family is lift handed except Iam Iwas married with lift handed wife and we have a lifthanded chiled