“I would pick my parents very carefully,” observed the Swedish exercise scientist Bengt Saltin, when asked what steps should be taken to become an Olympic sprinter.

That quote, if slightly tongue in cheek, carries an unavoidable truth, according to one of Europe’s leading sports scientists, Professor Tom Reilly. Asked by FIFA.com to what degree success in sport – and, in particular, football - is determined by genes, he replies: “Having two parents with outstanding athletic ability would give an individual a huge start. Having one would still give an individual a guarantee of a better than average start.”

There are numerous examples of footballers whose fathers have played the game – you can take one from each of the last three FIFA World Cup finals in Oliver Kahn, Youri Djorkaeff and Paolo Maldini – but for each of these, there are many more players with no such family connection to the sport. Being born into a sporting family offers no guarantee that a child will excel at sport.

However, it can at least provide him or her with some of the necessary physical attributes, according to Professor Reilly, who is Director of the Research Institute for Sport and Exercise Sciences at Liverpool John Moores University. Unlike sports like basketball (height) and American football (body mass) there is not one specific genetic gift required; instead the attributes required for a top-level footballer can be broken down into “physical and physiological skills, cognitive skills and game skills”, but inheriting the first two certainly provides a head start. 

“In football you’d inherit a good fraction of the makeup that would go with ability in endurance sport and we are calling soccer an endurance sport because it is – it goes on for 90 minutes, is played at a high tempo and you have to be able to recover quickly,” said Professor Reilly, whose university established the United Kingdom’s first sports science degree in the 70s.

“Also, it is a fast sport so you need to be quick as well as having good endurance. The likelihood is if you’re not born with a reasonable level of endowment at the start, training would not take you across the threshold value for a top-level performance.

“The physical features include appropriate height, the ability to jump, which is dependent on muscularity, and the ability to run and maintain a high tempo for 90-plus minutes – that is a function of the oxygen transport system. You need a whole range of physiological attributes as well as the attributes to be able to make and take tackles and cope with contact in the game.”

While the genes linked with performance have not yet been identified, science can at least predict an individual’s chances of inheriting certain physical attributes. Professor Reilly was able to offer the following estimates: “Height is really 85 per cent inherited, leg strength 80 per cent or thereabouts, body fat is down to 50 per cent, body shape maybe a bit less. With maximum oxygen uptake it varies but it is likely to be fairly high.”

These attributes only take you so far, of course. Ball skills (“to kick, pass, dribble, control the ball, head it and so on”) are a must, and cognitive skills (“when to time a run, how to angle a run, timing, anticipation”) too.  And as with physical endowments, some people are born with these other skills: a ready aptitude with ball games runs through the family of Gary and Phil Neville, the Manchester United and England pair, whose sister Tracey represents their country at netball.

Natural talent must be nurtured
Whatever an individual’s endowments, though, skills require practice and natural talent must be nurtured. An interesting case is provided by England midfielder Shaun Wright-Phillips and his brother Bradley, who play for Manchester City. Bradley is the natural son of former England striker Ian Wright, and Shaun his adopted son, but both benefited from the encouragement of their father. Indeed Shaun – whose natural father was not a sportsman - has recalled not being allowed back into the house until he had completed training drills in the family’s back garden.

Professor Reilly said the example of the Wright-Phillips brothers underlined the importance of sheer hard work – as well as good guidance. “There must be a level of physical attributes that have been inherited to start with but then probably the most influential factors in football would be the motivation and the support to be able to take up the game, play the game, and a passion for enjoying its skills and chalking up the hours of practice that are necessary to be successful at the top.

“So although physically the Wright-Phillips brothers are different, in their commitment to the game you are likely to have strong influences from peers, from parents, colleagues and others that have a role in mentoring individuals as you grow up.” And when, as in this case, a parent knows all about the pitfalls of the sport, it can only help.