Tuesday February 10, in Predazzo, Domen Prevc and his sister Nika Prevc won gold in the mixed ski jumping team event. A resounding victory… and almost a family one. Because with this medal, Domen becomes the fourth member of the siblings to stand on an Olympic podium. Their older brothers, Peter and Cene Prevc, already medalists at Sochi 2014 and Beijing 2022, had already written the Prevc name into the history of the Games. So, just a coincidence? Well-oiled training method? Or true biological transmission of excellence?
The Games, fertile ground for sporting dynasties
The phenomenon goes beyond Slovenia. The Olympic Games are full of brilliant siblings and bloodlines. In France, the Alphand, Manaudou and Karabatic families have also left their mark on their discipline. Even more recent, Léon Marchand, French swimmer and pool star, is none other than the son of two former Olympians, Xavier Marchand and Céline Bonnet, who participated in the Barcelona Games in 1992.
For Professor Jean-François Toussaint, cardiologist and sports physiologist at INSEP, this type of trajectory is not a coincidence.
“What we call heritability, or heredity, is absolutely masterful and continues to strengthen in Olympic performances.”
Podium probabilities exploding among siblings
With his team, notably researcher Juliana Antero, Jean-François Toussaint studied more than a century of Olympic history (1896-2016). Their study, published in 2018 (A Medal in the Olympics Runs in the FamilyFrontiers in Physiology), highlights a striking phenomenon.
On average, historically, an athlete competing in the Winter Olympics has around a 20% chance of winning a medal. But once a family link exists, the probabilities rise sharply.
“They are 40% if you have an Olympic medalist parent. They rise to 50% if you have a medalist brother or sister”. Among twins, the figures become spectacular: “We reach 70% for dizygotic twins… and up to 80% for monozygotic twins.”
In other words, it is factual: sharing the same genetic heritage considerably increases the probability of also sharing an Olympic destiny.
Genes and culture: a double heritage
But how can we explain this transmission and this excellence? For Professor Toussaint, two dimensions intertwine: biology and the environment.
“All the muscular, joint, skeletal, neurological, cardiovascular genetics, everything you need to have a champion, is transmitted 50% by the parents.”
In other words, if the latter have exceptional physiological capital, their children inherit an already optimized base.
But sports culture plays an equally decisive role.
“In these families, you grow up in a culture of effort, in a familiarity with training and competition. That matters a lot,” he adds.
In the Prevc family, ski jumping is part of everyday life. For Léon Marchand, swimming is almost a mother tongue. Pools, courses, competitions punctuate childhood.
“Siblings often choose similar disciplines. We don’t often choose curling by chance, for example. We stay in the same sporting universe.”
Genetics offers the potential. Culture activates and structures it.
An elite that is passed down?
The most impressive? The phenomenon even seems to increase over the generations.
“We now see medalists spanning three generations. And this percentage continues to increase” recognizes the professor. As if the sporting elite were consolidating, generation after generation, their physiological assets and their know-how.
However, nothing is automatic. Heritability increases the chances, but does not guarantee anything. The medal remains the fruit of years of training, discipline and seized opportunities.
But in Predazzo, when Domen and Nika Prevc shared Olympic gold, they embodied this fascinating alchemy between genes and culture. Proof that, sometimes, talent has to be worked on… but that it can also run through the veins.