Commentary on two recently published formal guidelines on management of "mosaic" embryos after preimplantation genetic testing for aneuploidy (PGT-A). - Gleicher N; Barad DH; Ben-Rafael Z; Glujovsky D; Mochizuki L; Modi D; Murtinger M; Patrizio P; Orvieto R; Takahashi S; Weghofer A; Ziebe S (Reproductive biology and endocrinology : RB&E, 2021)