The article is devoted to the most important section of perinatology — the development of the fetal brain. The correct formation of the fetal brain is the key to neuropsychic health in the later life of a child and an adult, determines his cognitive and intellectual abilities. The article presents a literary review of the latest world studies of the main processes of neurogenesis and corticogenesis (proliferation and migration of neurons, their specification and differentiation, cytoarchitectonic connection of neurons, the formation of neural networks and connections, synaptogenesis, elimination of excess cell elements and apoptosis, proliferation and differentiation of glial cells, myelinization). The intensity of histogenetic events dynamically changes at different stages of pregnancy. There are periods during which the developing fetal brain is characterized by increased vulnerability to adverse endogenous and exogenous factors. We provide clinical examples demonstrating that a violation of the prenatal program of fetal brain development (including iatrogenic ones) can be the basis of neurological and psychical diseases in a person’s later life. The peculiarities of the development of the fetal brain at different stages of pregnancy should be taken into account when planning therapeutic and surgical interventions during pregnancy.