I wrote a similar statement here once before, but it's something like this.... Nature vs. Nurture is an interesting debate, until your second child is born. Then you realize some things are just ingrained. One child is athletic, the other is not. One is an average student, one is a great student. One is quiet and reserved, the other is outgoing and talkative. And as much as you think you can influence or change some things, you eventually realize that some traits are just hardwired.
I know some brothers who are both baseball players. One is 6'3", has the gift, throws 90+ and was over 6' and throwing 80 coming out of 8th grade, and has a ton of potential. The other is 5'8", was always the other's catcher and has limited baseball potential. One played on top travel squads, the other played on local squads. The gifted one had little drive and may have blown his gift with poor decisions. The smaller one has pushed to become an excellent high school player with drive, and leadership potential.