Presenting expert evidence in criminal proceedings.

health care team is involved early, it is in a better position to provide continuing support for couples and families later found to be "at risk." General practice provides an opportunity for later targeted cascade screening-that is, investigating close relatives of people who have screened positive.' 6 The rationale for genetic screening services is to provide patients with informed choice. Some doctors voice the understandable concern that demand does not exist for these services. But recently 86% of older schoolchildren favoured screening for cystic fibrosis carrier status.9 In Trent region, antenatal patients have responded favourably to offers of screening for cystic fibrosis discussed opportunistically by a general practitioner (J W Fenby-Taylor, personal communication) and to screening for the haemoglobino-pathies. The primary care team's role goes beyond genetic screening tests; drawing an accurate family tree must be developed as an essential basic skill.'01' Family histories have begun to be recorded in family practices in North America and are often pictorially represented as a genogram."2 Patients and general practitioners can successfully collect basic genetic information .6 Recording of the pedigree in primary health care would also be useful in deciding whom to refer to genetics services. Information on families has to be collected and recorded within a reasonable time.'0 Two techniques have been considered: the self administered family history questionnaire (which takes one to two hours"3) and the structured interview (which takes about 20 minutes.'2) Furthermore, we are extremely impressed by our patients' ability to understand pedigrees and suggest that the value of family trees prepared by patients should be researched. We need to be confident that patients' recall is accurate and that the yield ofinformation is worthwhile; research suggests that this is likely. 4 15 In this district we are evaluating new approaches to collaboration between general practitioners and geneticists in providing a service to a specific ethnic minority group. The timing of the recording of the family history may be important. Although some authors advocate incorporating this into the preconceptional screening services offered to patients, older members of the family may be required to confirm and extend the information. After such enthusiasm a few notes of caution should be sounded. Firstly, patients need to be informed fully of the consequences-for example, the implications of pre-symptomatic genetic screening for life insurance.'6 Secondly, a recent circular from the Department of Health states that future genetic services will have to be funded from …