Lamarck was not batsh-t crazy after all. Your dad’s environment changes you in a non-genomic way. Discovering novel mechanisms of inheritance which influence the physical and mental health outcomes of subsequent generations is technically difficult, especially for a human population that is vastly heterogeneous for genetic, social and environmental factors. Preclinical research has been tremendously important for advancing our understanding of transgenerational effects and growing our awareness of heritable, non genetic factors dictating offspring health and disease susceptibility. The effects of maternal stress, diet and drug exposure on offspring health outcomes are well-known, and understandably more substantial than the paternal contribution given the intimate mother offspring interaction during pre- and post-natal periods. The extent of paternal influence was thought to be limited to inherited DNA, but recent evidence indicates that epigenetic modifications in the male germ line significantly alter offspring phenotypes. A variety of health parameters could be impacted on including risk for diabetes and cardiovascular disease. Changes to DNA methylation or small non-coding RNAs (e.g. microRNA, tsRNA) impact the complex epigenetic regulatory machinery and steer the developmental trajectory towards a distinct offspring phenotype. In this presentation, I will discuss recent work undertaken by my group to describe paternal environmental factors and their transgenerational effects on anxiety- and depression-related behaviours. We have found that moderate physiological stress in the founder generation is sufficient to change the behaviour of unstressed offspring. Using next-generation sequencing, we have validated previous studies of paternal stress and identified small RNA changes in sperm. We have also probed the effects of cognitive stimulation (environmental enrichment) and physical exercise (voluntary wheel-running).