The case for a coordinating centre for birth cohort studies.

Designing, piloting and proceeding with a longitudinal birth cohort is a major exercise. Here we outline ways in which a resource centre could be initiated to provide advice and training, a library of appropriate instruments and publications, provision for cross-cohort comparisons and a biobanking facility. The resource should be available for cohorts planned in the developed and developing world, as well as those countries in transition. We discuss possible strategies for funding such a centre.