Croswell believes we should define a planet simply - as something that goes around the sun and has the diameter of Pluto or more.

Croswell said the researchers weren't sure why the false-positive rate was higher for men, but it likely had something to do with the tests that were studied.

Ken Croswell: It would confer planet-hood not just on Pluto but on so many other things too, probably dozens - if not hundreds - of other objects in the solar system.