I'm honestly trying to stay away from crazy conspiracy theories, but here's someone who thinks it goes way beyond coincidence that there are so many Russian female tennis players, looking a lot alike, playing in the same style, getting into the top 20 players in the world.
How often has there been two players from one country getting into the top ten? These Russians are basically from an area around Moscow.
Cloning seems a but much, but: sperm donation from the same top player?
Via Six Until Me/Grand Rounds.