Science has shown that almost everything about us is shaped by both nature and nurture: by genetic variations in our DNA and by our experiences. But although our DNA does not change during our lifetime, the effect it has on us can be influenced by our social and physical environment. Our previous work has shown that one important environment is where we grow up. For example, the effect of some genetic variations may be seen only in the centre of a large city, or only in the south of the UK. In other projects we have looked at these geographical influences on a national scale. Now we would like to use data from the Children of the Nineties to zoom in on a single city region to map how local environments draw out or mask the influence of our genomes as we grow up. We will be exploring a range of complex traits such as Autism Spectrum Disorder (ASD), Attention Deficit Hyperactivity Disorder (ADHD) and asthma. We hope that this will help us to identify important new environments and design policies to reduce the risk of mental and physical health disorders in childhood.