Late Developers and the Relative Age Effect in US Youth Soccer

If your child is small for their age, young for their age group or a late developer, it can feel like the door is closing at 12. It isn't. One of the best-documented biases in youth soccer works against younger and later-maturing players, and it is worth understanding now that US age groups are changing.

The relative age effect

Youth soccer groups players by a cutoff date, so a player born just after the cutoff can be almost a full year older than a teammate born just before it. The relative age effect is the tendency for coaches and selectors to favor those older players. A study of 3,364 US girls in the 2021-22 talent identification pathway, when age groups ran January to December, found 34.8% were born in January to March and only 13.8% in October to December, against roughly 25% each if birthdays were evenly spread.

Birth year vs school year from 2026-27

U.S. Soccer announced in 2015 that youth registration would move from an August 1 cutoff to January 1 birth years. In late 2024 it dropped that mandate and let its member organizations choose. For the 2026-27 season:

• US Youth Soccer, US Club Soccer and AYSO group players by school year, August 1 to July 31. They first announced September 1 in March 2025, then moved to August 1 in June 2025. A U13 player in 2026-27 was born between August 1, 2013 and July 31, 2014.
• MLS NEXT uses school-year groups in its Academy Division but keeps January to December birth-year groups in its Homegrown Division.

Changing the cutoff does not remove the bias. Researchers expect it to shift which players are advantaged: under an August 1 cutoff, players born in August, September and October are the oldest in their group, and those born in June and July the youngest.

Maturation: the bigger hidden factor

Birth month is only part of it. Girls usually start their growth spurt around 11 and a half, but it can begin as early as 8 or as late as 14, and boys typically trail by about two years. Researchers note that maturity-related differences in size, strength, speed and power are greatest between about 11 and 14. An early maturer can dominate at 13 on size alone, while a late maturer may simply be earlier in the same journey.

Bio-banding and late-developer camps

Bio-banding groups players by biological maturity rather than age. U.S. Soccer has run bio-banded events in which sport scientists estimated each player's maturity from their height, weight and their parents' heights, so that late developers are not, in its words, "squeezed out" of the highest levels. It has also run a Futures Camp for later-maturing players and those born in the second half of the calendar year.

What late developers should do

• Build the pillars that last. Technique and game understanding don't depend on size; see the four pillars.
• Be patient through growth spurts and manage training load; our nutrition and fitness guide covers the injury risks.
• Choose minutes over badges. A level where you play beats a bench at a bigger club; see routes without an elite club.

Being overlooked at 12 is often a snapshot of growth timing, not a verdict on talent. Take the free development assessment to see which parts of your game to work on next - its physical read is adjusted for late developers, and it describes where your game is today, not where it will end up.

Sources: Finnegan et al., Biology of Sport, 2024; Smith et al., Frontiers in Sports and Active Living, 2021; SoccerWire on U.S. Soccer's 2024 decision; AYSO age groups; MLS NEXT age groups; HealthyChildren.org (AAP); U.S. Soccer on bio-banding.

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