Semen donors have been required to register with the Human Fertilization and Embryology Authority since its formation in 1990. Since then many clinics have reported a shortage of donor semen for donor insemination treatment. Is this because potential donors are worried about the protection of their anonymity? No published studies are available concerning the attitudes to semen donation in the UK. It was against this background that an investigation of the attitudes of potential semen donors was carried out. Four dimensions were investigated: (i) motives, (ii) personal detachment and involvement, (iii) detachment and involvement with respect to recipients, and (iv) detachment and involvement with respect to offspring. A total of 55 potential semen donors completed the attitude questionnaire from semen donation programmes in three in-vitro fertilization units. The questionnaire format was found to be an effective method of data collection for this sensitive area of research, and the major findings were (i) 89% of potential donors required confidentiality and guaranteed anonymity; (ii) 82% did not mind providing non-identifying information to the recipients and offspring; (iii) 69% of potential donors expected financial reward; and (iv) 69% did not welcome counselling.