This study was conducted to determine the parent-offspring genetic structure of the pedunculate oak (Quercus robur L.),sessile oak (Q.petraea[Matt.]Liebl.)and their hybrids.Forty half-sib Quercus families and their maternal trees originating from one tree stand in southern Lithuania were analyzed using SSR and RAPD markers.Based on a preliminary study of leaf morphological traits,the individuals separated into six groups.The studied halfsib oak families were also compared for allelic diversity,including group variations;genotypic structure;genetic diversity;and the degree of genetic subdivision and differentiation.The level of genetic variation and subdivision was lower in the hybrid families than in the families of the parental species.Genotypic analysis of the half-sibling offspring showed the asymmetric nature of interspecific hybridization processes of pedunculate and sessile oaks in mixed stands.