A few months ago, I read an interesting post on the Freakonomics blog about the effect of birth date on soccer stars. I thought it was an interesting effect at the time, and pondered whether it could pop up in other sports.
Well, apparently it affects minor hockey in Canda, too. From the article:
"A new study shows that kids born later in the year are more likely to be filtered out of hockey at a young age, even though they will end up being as big and strong as the players who have birthdays earlier in the year."
What I find most interesting about this is that I remember, as a kid, noticing this. On my AAA and Junior hockey teams, we almost never had a kid who had a birthday in the fall (except one, who was tiny and particularly skilled). We never thought much about it at the time, but it's definitely something that exists.
This is definitely an indication of places where sublte bias come in to play - we notice this in interviewing and hiring all the time. As much as you can say that you're not biased towards a given outcome, the unconscious mind is a tricky thing, and leads to biases that you never would have believed.
So, if you're aiming to have a kid who plays in the NHL, it looks like you should be trying to get pregnant in the early spring. (The saddest part of that is that I know some parents who would do exactly that.)