Depression and antisocial behavior are important public health problems. The degree to which parent psychopathology influences the early manifestation and course of these problems in children via genetic and/or environmental mechanisms is unclear. We estimated the influence of maternal depression and antisocial behavior on level and change in child externalizing and internalizing behaviors across early childhood using data from a prospective adoption study. Participants were 346 matched triads of physically healthy children, biological mothers (BM), and adoptive mothers (AM). Latent growth curve models were estimated using AM reports of child internalizing and externalizing behaviors at ages 18, 27, and 54 months. Child outcome growth factors were regressed on BM lifetime histories of major depressive disorder (MDD) and adult antisocial behavior assessed by interview, and AM self-reported depressive symptoms and antisocial behavior. Mediation of genetic effects was tested via BM reported obstetric complications and adoptive father-reported child temperament at age 9 months. Both child problem types showed linear increases over time. Predictors of intercept (18 months) but not slope were identified. BM MDD and antisocial behavior predicted child externalizing and internalizing behavior, respectively, and AM depressive symptoms and antisocial behavior predicted both child outcomes. Child temperament and obstetric complications did not explain BM effects. This adoption study distinguished risks conferred by biological mothers’ depression and antisocial behavior to children’s behaviors from those associated with adoptive mothers’ related symptoms. Future studies should examine gene-environment interplay to explain the emergence of serious problem trajectories in later childhood.