A thorough analysis of testicular physiology during prepuberty is needed to understand how the gonad is primed to support spermatogenesis later in life, and how this could impact the fertility potential of an individual. During minipuberty – the short period after birth when the hypothalamic-pituitary-testis axis is transiently active – Sertoli cells are active and proliferating; however, the changes these cells undergo, and the underlying mechanisms are not fully understood. This project will provide insight into the gene regulatory networks behind minipuberty in the testis. Through a multiomic approach that allows combined analysis of gene expression (RNAseq) and open chromatin regions (ATACseq), we will identify genes and their regulators (mostly transcription factors) with differential behaviour between the neonatal and minipubertal periods, using the common marmoset as an experimental model. Our findings will shed light on prepubertal testis development and could potentially lead to a novel treatment approach for children with absent minipuberty.