Mold needs two things to survive and spread: moisture and food. Because it's susceptible to moisture, traditional paper-faced drywall is mold's favorite sandwich, with two outer faces of paper as the bread and the gypsum stuck in the middle as baloney. Gypsum is a mineral, and though mold cannot digest it, the cellulose in the paper can be degraded by some molds. The drywall paper is like bread in another way: the paper contains up to one percent starch, another nutrient for mold.
A great alternative to traditional, paper-faced drywall is Georgia-Pacific's DensArmor® Plus, a relatively new type of drywall in which the paper faces have been replaced by thin, fiberglass mats. It's moisture-resistant, and because fiberglass, like gypsum, is a mineral, there are no nutrients on which the mold can grow.