Growing up, we all knew at least one set of twins. It's as if it was a pre-requisite for most American elementary schools to feature them, wearing the same clothes on picture day, speaking that weird "twin-speak" that nobody but them could understand (or care about). They seemed to have an advantage.

Later on in life, we would hear about the "uncanny" abilities twins had that we common babies, born from a single embryo, did not possess. Like, twins could just think about each other and one of them would immediately pick up a phone from Oregon and call the other in Pennsylvania and discuss the disposition of their cats.

But, like most things in life, the whole "twin thing" began to lose its luster the older and, presumably, wiser we all became. The whole split zygote thing didn't seem to offer as much of an advantage as was believed. Aside from a few (alleged) cases where one twin would substitute for the other during exam time, little more was made of the distinction (and even then, it was only if you were an identical twin, so good luck).

There have been plenty of times when one half of the twin equation fails to achieve heights enjoyed by the other. Nowhere, perhaps, is that more amplified than in the world of sports.

Jim Thorpe had a twin brother named Charlie. Jose and Ozzie Canseco hardly shared the pages of the record books (if not the needle). And did you know that John Elway has a twin sister named Jana? Where's her Super Bowl ring?

And while some believe the Vitali and Wladimir Klitschko heavyweight brotherhood are the result of twinship, they are wrong: Vitali is five years older and has a slightly different nickname. Venus and Serena? Not twins.

The world of sports actually records very few "twin" wins. Ronde and Tiki Barber both set records for the respective teams, but they never came near the heights achieved by Bob and Mike Bryan, the twins from Camarillo, Calif. Those two have dominated the doubles tennis field in record-setting fashion.

They have won more doubles titles than any team in history -- 72 as of this writing -- and have been the world No. 1 doubles players for almost a half-decade. They have set records in match wins (more than 600) and they even hold the record for attracting the largest crowd in tennis history at 27,200 (the Billie Jean King exhibition victory over Bobby Riggs in front of 39,472 at the Astrodome wasn't an "official" match).

So there you have it. In one fell swoop of their tennis rackets, the Bryan brothers have dispelled the notion that for every Mario Andretti there must be a non-racing brother Aldo, and that the U.S. cannot be competitive in worldwide tennis competition.

When taken together, they rewrote the record books -- and they did so doublehandedly.