We will link the above variables to the data on atopic outcomes and confounders (and PSAI score) which we already have, and carry out appropriate multivariate analyses in boys and girls separately. We will examine relations of digit ratio to the other variables above, and to testosterone levels in pregnancy in the subset with these data. We will stratify by maternal atopic disease and parity (especially number of older brothers which has been linked to digit ratio and to atopy), and stratify the handedness analyses by family history of atypical handedness. We could also relate maternal handedness to atopic disease in the mothers. If we confirm novel associations with digit ratio we will write these results up first.