seems like in most sports (hockey, tennis, motorsports are the three I'm most familiar with), the oldest child usually do not do as well as the younger siblings. parents probably adjust their methods to be more effective and the experience gained with the first child helps them make better decisions. also, being able to train with an older, stronger and better sibling from a young age is a huge advantage for an aspiring athlete.
Federer and Nadal are the firstborns, but have younger sisters who are not athletically inclined
Serena has won many more Slams than Venus, though Venus is really a very very good player in her own right who happened to be unlucky in a sense.
Djokovic is a bit of an exception, in that his younger brothers have not shown his level of success in tennis.
Murray, Blake, Roddick, Filip Peliwo (who's the youngest of three) fit the usual trend
Maurice and Henri Richard - Maurice was 10 years older and a more explosive player, but Henri had the longer and better career overall
Sean and Chris Pronger - Chris was an all-star defenseman, while older brother Sean was a career minor-leaguer (and the author of a pretty funny autobiography)
Alain and Mario Lemieux - Alain only played a few games in the NHL. Mario is a hall of famer
Jacques Villeneuve Sr. and Gilles Villeneuve - older brother stayed in Canada and (still) races snowmobiles. little bro went to drive for Ferrari and briefly was one of the best drivers on the planet
Wilson and Emerson Fittipaldi
Pedro and Ricardo Rodriguez - Both died very young but Ricardo was supposedly more talented
Aldo and Mario Andretti
Last edited by thejackal; 02-26-2013 at 12:23 PM.