A Medal in the Olympics Runs in the Family: A Cohort Study of Performance Heritability in the Games History.

Elite performance in sports is known to be influenced by heritable components, but the magnitude of such an influence has never been quantified. We hypothesized that having a former world-class champion in the family increases the chances of an athlete to repeat the achievement of her or his kinship. We aimed to measure the heritability of a medal in the Olympic Games (OG) among Olympians and to estimate the percentage of the genetic contribution to such a heritance. Twin-family study of a retrospective cohort. All the 125,051 worldwide athletes that have participated in the OG between 1896 and 2012 were included. The expected probability to win a medal in the OG was defined as the frequency of medallists among Olympians without any blood kinship in the OG. This expected probability was compared with the probability to win a medal for Olympians having a kinship (grandparent, aunt/uncle, parent, or siblings) with a former Olympian that was a (1) non-medallist or (2) medallist. The heritability of the genetically determined phenotype (h) was assessed by probandwise concordance rates among dizygotic (DZ) and monozygotic (MZ) twins ( = 90). The expected probability to win a medal in the OG was 20.4%. No significant difference of medal probability was found in the subgroups of Olympians with a Non-medallist kinship, except among siblings for whom this probability was lower: 13.3% (95% CI 11.2-14.8). The medal probability was significantly greater among Olympians having a kinship with a former Olympic Medallist: 44.4% for niece/nephew (33.7-54.2); 43.4% for offspring (37.4-48.6); 64.8% for siblings (61.2-68.8); 75.5% for DZ twins (63.3-86.6); and 85.7% for MZ twins (63.6-96.9); with significantly greater concordance between MZ than DZ ( = 0.01) and h estimated at 20.5%. Having a kinship with a former Olympic medallist is associated with a greater probability for an Olympian to also become a medallist, the closer an athlete is genetically to such kinship the greater this probability. Once in the OG, the genetic contribution to win a medal is estimated to be 20.5%.