Biobanks that are run on an opt-in basis depend on people having the motivation to give and to trust in those who control their samples. Yet in the UK trust in the healthcare system has been in decline and there have been a number of health-related scandals that have received widespread media and public attention. Given this background, and the previous public consultations on UK Biobank, the paper explores the way people express their trust and mistrust in the area of medical and genetic information through discussions in six focus groups held in different areas of Britain. The themes that emerged in the discussion were the special character of genetic data; the ease with which information spreads; the public/private divide in genetic research; the potential of genetic information to harm people; choice, consent and lack of control; and the difficulty of establishing trustworthy governing arrangements. The expert agenda of policy-makers and medical ethics does not address the broader concerns expressed by participants. It seems that public consultation and the language of openness and transparency may not be sufficient to establish trust in the governance of genetic databases. Donors will be asked to give freely without any return but the participants' perception of those using the samples is that they are motivated by success and profit rather than healthcare priorities. In this context altruism seems naive and even dangerous. In order to place their trust well people need evidence of a relationship with obligations and expectations on both sides.