Some findings suggest that offspring of older parents are at an increased risk of various disorders, such as cancer, diabetes type 1, obsessive-compulsive disorder, autism, schizophrenia, and bipolar disorder. The role of epigenetics in these associations is beginning to be explored. The most robust and readily measured epigenetic modification is DNA methylation, which is a normal and mitotically heritable change that regulates gene activity in the absence of underlying changes to DNA sequences. Epigenetic analysis may provide new insights into the mechanisms through which genetic and environmental factors jointly contribute to shape risk profiles. Exploiting differences in levels of DNA methylation and also genetic variants correlated with methylation levels according to parental age might contribute to our understanding of the extent to which associations between parental age and offspring health-related outcomes are explained by socioeconomic or biological factors. Aims and objectives: The overall aim is to examine the association of parental age with offspring DNA methylation levels. Specific objectives are: 1.) Examine the association of maternal and paternal age with offspring DNA methylation patterns. 2.) Compare the association of maternal age and offspring DNA methylation with that of paternal age with offspring DNA methylation. 3.) Examine genetic variation around any methylated sites that are related to parental age to identify genetic variation that might be causally related to that methylation. 4.) If associations are found between maternal / paternal age with offspring DNA methylation we would then explore whether this mediates associations with adverse offspring health outcomes; this would involve standard association analyses methods and also (if possible) genetical genomics approaches.