The funny thing is that this idea of "many worlds" has been condemned by Fathers, Doctors, Theologians, and even Popes as heretical (Ss. Augustine, Isidore and Jerome, for example). And some these days would like to stretch "many worlds" to be something like multiverse theory or whatever, but in their context, these individuals were condemning the proposition of other places like earth and that earth is just another "star" (e.g. planet) among many, that contain life.
"Nothing under the sun is new," Eccl. 1:10