FDA is issuing this guidance to outline recommendations on conducting the mouse embryo assay (MEA) to support premarket submissions and lot release of assisted reproduction technology (ART) devices. The majority of ART devices directly or indirectly contact gametes (i.e., sperm and oocytes) and/or embryos during their intended use. MEA is used to assess the potential for embryotoxicity of devices that contact gametes and/or embryos. Several classification regulations under 21 CFR part 884 include special controls that require MEA testing or information. MEA may also be used to support premarket submissions for other devices that are intended to contact gametes and/or embryos during their use. However, there are no voluntary consensus standards that describe how to conduct the MEA. This guidance provides recommendations for conducting the MEA to support premarket submissions for devices that are intended to contact gametes and/or embryos and to comply with the special controls for those devices classified under 21 CFR 884 that require MEA testing or information.