Parental influences on offspring phenotype occurring through pathways other than inherited DNA are known as parental effects (i.e. epigenetic modifications). Such effects have been demonstrated to affect two traits that are very widespread and of fundamental importance in the animal kingdom with clear fitness consequences: laterality of brain and behaviour and personality traits. For example, reproducing groups of adult sticklebacks exposed to predation cues produce offspring with decreased antipredator behaviour and reduced activity levels. This study investigated the impacts of parental effects on the development of brain lateralization, personality traits and somatic growth of offspring. Groups of reproducing sticklebacks were treated with a combination of several predator cues or lack thereof during egg production. Soon after laying, eggs were removed and a part of the clutch was reared in standard conditions until 12 weeks post hatching, whereas the other part was used for maternal hormone analyses of steroid in the androgenic and cortisol pathway. Results are currently being analysed. So far we found that offspring from predator-exposed parents were smaller than control offspring likely due to the ecological stressor of the predation consistent with the possibility that these eggs contained elevated levels of corticosteroids. We expect to find that our results support the hypothesis that stickleback parents influence the development of lateralized behaviour, personality traits and growth of their offspring via eggs to match their future environment.