Of the 3457 exoplanets currently known, 146 actually orbit binary star systems (and 39 orbit multiple star systems with three or more stars).
However, recent simulations indicate that planets are just as likely to form around binary star systems as single-star systems. In the past, scientists thought that planets would be unlikely to form around binary stars. A NASA depiction of a theoretical viewpoint from Kepler-16b's orbit of its two suns.