HFM1 and Azoospermia: HFM1 is essential for mammalian fertility as mutated HFM1 was found in human patients with azoospermia or POI syndromes (Baudat et al., 2013; Wang et al., 2014; Zhang et al., 2017) and removing HFM1 causes a drastic reduction of COs and partially affects synapsis in mice (Guiraldelli et al., 2013).