While fragmentary data have very recently suggested putative roles of specific miRNAs in the control of Kiss1 in other cellular contexts, ranging from ectopic pregnancy33 to brain cancer metastasis34 and immortalized GT1-7 cells35, our data provide conclusive in vivo evidence for an essential role of miRNA biogenesis in Kiss1 neurons for proper functioning of the reproductive axis in adulthood, and further illustrate the indispensable role of kisspeptin input onto GnRH neurons for adult fertility. Here, GNRH1 is linked to brain cancer.