No other planet yet discovered to support life as we know it.
Emphasis on 'as we know it'.
Life could have developed differently (been created differently, whatever you believe) on different planets. Somewhere out there on Planet X is a race of beings like us that survive on methane and have a core body temperature of twenty-thousand degrees and the planet is twenty feet away from the sun. They look to earth and see a barren and inhospitable freeze-hole with no breathable air.