Adrenarche is the prepubertal increase in synthesis and secretion of the androgen dehydroepiandrosterone (DHEA) from the zona reticularis (ZR) of the adrenal gland. It is widely considered to be an early-life phenomenon unique to humans and only some non-human primates. The functional consequences of the adrenarche for childhood brain development are not fully understood; ethical restrictions preventing experiments in humans and young primates limits our mechanistic understanding of the adrenarche and its significance. The factors driving the developmental change in ZR androgen activity have not been fully identified; they may be intra-adrenal, extra-adrenal, or both. While discussion of the adrenarche focusses attention on the pre-pubertal surge of DHEA/DHEAS, these steroids are in fact dynamically regulated from before birth, and therefore may be regulated by factors affecting fetal growth, the placenta, the hypothalamic-pituitary axis, or indeed the spino-sympathetic innervation of the adrenal medulla and ZR. In addition, it is now known that DHEA/DHEAS is synthesized in the brain during development in some species, but it is not known if this is co-ordinated with adrenal production of this androgen. If DHEA/DHEAS is indeed important for brain maturation both before and after birth, and important for the adaptation and rewiring of the postnatal brain to the new and ever-changing challenges of real-world and social life, we suggest that the difficulty of investigating these neurodevelopmental phenomena in humans and a few primates could be resolved by looking for new animal models in which adrenarche-like changes occur during pre- and post-natal development.