Apart from Mendelian inheritance, fathers use alternative routes for intergenerational information transfer. One of these is a complex, dynamic and environment-sensitive pool of sncRNAs that are stored in mature spermatozoa1, delivered to the oocytes at fertilization9, and influence embryonic development10,11 and adult phenotypes1,2,3,4,5,6,7,11. Production of mature haploid spermatozoa from sperm