A new area of studies - ontogenetics or developmental psychogenetics - is presented. It deals with genetic and environment factors' role in individual differences' forming in ontogenesis and individual trajectories of development. Theoretical basis of developmental psychogenetics is analyzed. Possible ways of interaction between psychogenetics and psychophysiological and psychological notions are discussed. Interdisciplinary studies uniting these three branches of science (developmental psychogenetics, developmental psychology and psychophysiology) enable one to solve some theoretical and applicational problems, while another methods do not give unequivocal results.