Not to say that monkey isn't a man but my theory on the williams "sisters" is that they are creatures of gene-doping. I did a huge study in college on athletic performance enhancing techniques. It is theorized that Florence Griffith Joyner (Flo-Jo) was one of the first to be gene doped. The williams monkeys are superior athletes (for females) but have 100% different body types. Of course it isn't impossible for siblings to be different but venus is your tall, thin, lady-like body while serena is short, stocky, and man-like body with huge musculature. We know it isn't uncommon for siblings to be all athletically gifted -- staal brothers (3 of them) all play NHL, Watt brothers both are NFL and I'm sure many others. The difference though is that their body types are very similar to their siblings.