- Christopher Hammond, Twin Research and Genetic Epidemiology Unit, St Thomas’ Hospital, London, UK;
- Accepted March 2, 2007
- First published March 14, 2007.
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.