text: what's the odds of being left-handed in the world?   about 10% of people all over the world are left-handed (mcmanus, 2002). however, if you are wondering risks/odds, one area may be in familial sinistrality (how many family members you ahve that are left-handed).  handedness runs in families, and  even having a grandparent (who it can be argued will have be of little imitative effect) who is left-handed increases a person’s chance of being left-handed. the effects of parental sinistrality are seen below    effects of parental sinistrality (mcmanus, 2002)  parents’ handedness (respectively)/ percentage of left-handed children  right & right   9.5% right & left    19.5% left & left     26.1%   it is evident that children born to at least one left-handed parent are more likely than the rest of the population to be left handed.  i hope that helps! all the best!