It's a joke told by every minister in every church everywhere at
   some point in time. There's a lot of variations of it, but it's
   basically the same joke.

   Some get really specific when distinctions between churches get
   finer and finer. It's why I laugh out loud anytime someone says,
   "Christians do [x]" or better yet, "Theists believe [x]". It's
   so ridiculous and completely misses all the marvelous
   in-fighting and politics.

   I get the same laughing fit when someone goes, "Science believes
   [x]" because the same exact stuff happens among the various
   Sciences, within the same fields, etc. It's what makes them so
   interesting - the people and group dynamics.