Parental health during pregnancy is a key driver of long-term brain health of offspring. Evidence suggests that children born to obese mothers have lower IQ and poorer memory compared to children of lean mothers. However, much less is known about the impact of paternal obesity on the brain function and mental health of their children. This project will analyse the cognitive function, memory performance and mental health of infants, children and adolescents born to obese and overweight vs lean fathers. We will also investigate the impact of paternal BMI on the brain structure of their children. In addition, we will evaluate the potential additive effect of maternal and paternal obesity on these outcomes. Where possible, we will include relevant genetic information in the analyses to ensure that conclusions about parent-child outcomes are not simply due to gene inheritance. Results from this project will generate important information about whether parental obesity influences the long-term brain health of offspring and the risk of developing neurodevelopmental disorders. The impact on long-term brain health up to young adulthood, as characterised in this study, may also have consequences for the future risk developing neurodegenerative disorders given the primary role of cognitive reserve in protecting against these age-related disorders. This study will play a key role in providing novel insight and new targets for interventional strategies to ensure brain health across the lifespan in the context of an increasing, global at-risk population.