Gravity at least is understood and proven, so whilst the idea of magical fairys could be true there is at least evidence which would suggest otherwise.

The Bible if taken not quite as literally does tend to agree with science on a fair few points e.g The idea of let there be light is very easy to imagine refering to the big bang and the order which god created the various things on the planet such as the land and seas is actually pretty accurate as well, also it has been proven that all human life can be traced back to one woman.