te•rat•o•gen•e•sis(tə rat′ə jen′ə sis, ter′ə tə-),USA pronunciationn.[Biol.]the production or induction of malformations or monstrosities, esp. of a developing embryo or fetus. Also called ter•a•tog•e•ny(ter′ə toj′ə nē),USA pronunciationte•rat•o•ge•nic•i•ty(tə rat′ō jə nis′i tē, ter′ə tō-).USA pronunciation