Martin Leeb performed his PhD thesis in the Wutz lab at the IMP in Vienna. From 2011 to 2015 he was a post-doc in the lab of Austin Smith at the Cambridge Stem Cell Institute. Since 2015 he is group leader and since 2021 Associate Professor at the Max Perutz Labs where the Leeboratory works on deciphering the molecular control of cell fate decisions. We address fundamental questions in developmental biology: How are we made? How are cell identities defined and maintained in order to provide the right cell type at the right time for proper development? What are the central molecular players for cell-fate choice? Our main research efforts focus on some of the first differentiation decisions taken during embryonic stem cell commitment.The Leeboratory approaches cell fate choice from multiple angles. We study epigenetics, RNA biology and signalling to pursue a holistic approach to understand differentiation. We use genetics and high-throughput methodology combined with systems biology approaches to delineate the molecular rules of cell-fate decision. Embryonic stem cells and various differentiation strategies are our main experimental model systems.