A report by the CIES Football Observatory has suggested that players born in the first months of the year are at a significant advantage when it comes to the development of their playing careers.
According to the study by the Swiss-based research group, which examines a sample size of 28,685 players across 31 European leagues, they found that the average player is born in the first half of the calendar year - significantly more than the figure for the average citizen.
In the breakdown of months, 11 per cent of players in the sample were born in January, whereas the figure is just over 8 per cent for the average member of the population.
Meanwhile, 19 per cent of footballers were born in the final quarter of the year, which is a full 5 per cent lower than the corresponding number for the population as a whole.
Only in England, did players have birth dates on average after July 1st, with the explanation that the cut-off point for selection is based on school dates of September 1st instead of January 1st.
According to the study's conclusions, the findings suggest the "existence of a selection bias favouring players with a precocious physical development".
The report explains the importance of early birth days by stating that "as youth competitions are generally organised on the basis of the year of birth, athletes born in January, February or March have a clear advantage over those born in October, November or December of the same year" when it comes to development.