The article discusses the change on the brains of male marmosets by fatherhood. The article highlights the association of fatherhood with changes in the prefrontal cortex (PFC) that comprises neuropeptide receptors and are known to mediate parental behaviour including vasopressin, oxytocin and prolactin. It also outlines that marmoset fathers hold higher density of dendritic spines on pyramidal cells in II/III layers of the PFC than that of non-fathers.