Related to the older sibling thing, I once read something that I found interesting. Unfortunately, I can't find the source right now but from my recollection the story was that there is a pretty strong correlation between being born in September or October and being a MLB Baseball Player but, there is almost zero correlation regarding birth month for HOF MLB Players.
The theory as to why:
The Little League cutoff date is August 31 so:
Suppose you and I grew up together and we were both good baseball players. Now further suppose that you were born on September 1 but I was born two days earlier, on August 30. Even though we are almost exactly the same age, at every level of Little League, you'll be the oldest guy on your team and I'll be the youngest guy on my team. Consequently, even if we are EXACTLY equal as baseball players, you will be MUCH better relative to your team than I am relative to my team because the other guys on my team are all older than us while the other guys on your team are all younger than us.
If we both have natural talent at the borderline MLB level (which is a VERY high level of talent), you are MUCH more likely to make the MLB than I am because you will be the best player on your team at every level. My exact same talent, however, may well get missed because the other boys that I play with are older so my VERY high level of talent is at least partially offset by the fact that the boys I play with and against are up to a year older than us while your VERY high level of talent will be accentuated by the fact that the boys you play with and against are up to a year younger than us.
When you move up to guys SO good that they will wind up in Cooperstown the birthdate thing doesn't matter anymore. They'll still stand out even if they are born in late August and spend their Little League years playing against guys up to a year older.
I wonder how much of this is not due to persistent differences that come from it, but due to people quitting sports?
I was born in late July. I was also very big for my age. I played football where they had age and weight cutoffs for the divisions. I think I started in 3rd grade and was in the class that was maximum 85 lbs and maximum 5th grade. While I was very close to the maximum weight, I was NOT anywhere near as physically developed as kids who were 5th graders but near 85 lbs--and made especially disparate being one of the youngest people in my grade. Some of those 5th graders could have had closer to three years extra physical development on me than the two that you'd expect due purely to grade difference.
So what happened? I didn't really enjoy it much. I started martial arts in 7th grade, and played football through the end of 8th grade, but because I didn't enjoy it, I ended up quitting football and sticking with martial arts. I've always thought that maybe I just was more suited mentally to individual sports than team sports... But would that have been different if I was consistently one of the
oldest people on my teams rather than consistently one of the
youngest--often by several years? Maybe I would have enjoyed it more if it wasn't a Sisyphean experience.
I've always thought if I stuck with football, I might have been good enough to get a low-level look at a scholarship somewhere. Hell, I was 6'4" and 225#, LEAN as hell, when I graduated HS. And that was without any significant weightlifting. With a strength program I could easily have been 250# and given a flyer look by a recruiter just on potential. Not OSU, or even Purdue, of course... But low FBS or high FCS? Might have had a shot.
But I never pursued it because I didn't find enjoyment. And as I have the perspective that hindsight gives, I wonder if I didn't enjoy it because I was constantly playing against kids two years older and two developmental years stronger than me.
