The Doctor posted:HSHULER, Not for the soul purpose of sports. However boys do develop a little stagier than girls. Fine motor skills such as tying shoes, and holding a pencil or crayon, girls pick up sooner. Boys would prefer going barefoot and throwing rocks while girls can color inside the lines. Some studies suggest a boy should start school a year later when their fine motor skills start kicking in.
Back to your question, there has been much discussion about birth dates right after the cut off. These kids are bigger, they make the better teams, they get more playing time, they continue to advance because of this through the years. You can find some results online of what month has the most MLB birthdays. They changed the cutoff from Jan 1st to May 1st about 10-12 years ago to help the age and grade match up a little better, a whole year can make a big difference.
I agree that a year can make a difference which is why I posed the question. I know several families who have done this but only two will openly admit it was foe athletics while the others spin it to sound good.
If the data shows that older players are more successful, why is it taboo to say the I held my kid back because I thought he'd have a better chance for an athletic scholarship?