Health Update:: Double bind

FOUR hundred twin sisters over the age of 40 are needed by doctors at St Thomas' Hospital, London, researching the gene which causes the bone- thinning disease osteoporosis. Volunteers will be asked to undergo a blood test that can identify the presence of the gene and predict a woman's risk of developing osteoporosis. Twins interested in taking part should contact Dr Tim Spector (071-922 8137).