In flowering plants, the pollen grain—the male gametophyte—interacts with the diploid sporophytic tissue of the pistil before liberating the male gametes in the vicinity of the female gamete. During this gametophyte-sporophyte interaction the male gametes are effectively screened by the pistil ensuring the entry of only the appropriate pollen tubes into the embryo sac. This review summarises recent investigations on pollen recognition and rejection, explains the current understanding, and projects future lines of study.