Key cells divide asymmetrically during the development of multicellular organisms to give rise to offspring with different fates. In the Drosophila external sensory organ, asymmetrical division depends on polarization of the precursor cells during interphase and the consequent unequal distribution during mitosis of the protein Numb, which determines cell fate. Gonzalez discusses recent research implicating the mitotic kinase Aurora-A in the asymmetric localization of Numb in sensory organ pI precursor cells, a new function that appears to be independent of Aurora-A's known roles in regulating centrosomal maturation and the organization of mitotic spindle microtubules.