A 35 year old woman with a family history of breast cancer was in need of advice. Her two sisters, aged 34 and 38, were healthy and not affected, but her mother had developed breast cancer at the age of 48, and her mother's paternal aunt had developed it at 39 (figure). The sisters lived in different parts of the United Kingdom. Her elder sister had been told that this family history was not important and that she would not need any screening until she was eligible for the national screening programme, whereas her younger sister had already had a mammogram and been told that she should have these yearly from the age of 35. The patient was confused and asked her general practitioner whether she should have mammography. The general practitioner wrote to the local genetics service for advice.