Boris Tezak is a developmental biologist with a particular interest in understanding how the incubation environment can influence cell fate decisions and organ development. Currently, his research centers around the process of ‘gonadal sex determination’ in reptiles. Unlike most organs whose fate is pre-determined, the gonad arises as a bipotential primordium with the ability to become two distinct organs (ovary or testis). This makes the gonad an ideal system to study cell fate decisions and organogensis. In many reptile species, incubation temperature controls gonadal sex determination. His work focuses on the molecular mechanisms by which, primarily turtle embryos, can integrate environmental cues to direct the development of an ovary or a testis.