Kepler-47 shows that binary stars can host planetary systems

Kepler-47, a binary start system, is shown to have two planets orbiting the eclipsing pair of stars. The outer of the two planets resides in the "habitable zone" where liquid water could exist.
Kepler-47: A Transiting Circumbinary Multiplanet System, Orosz et. al, Science, 21 Sep 2012 1511-1514