Recent advances in the field of reproduction have made it possible to obtain preembryos and to use them in many research applications. These include research into improving methods of IVF treatment, contraceptive research, preimplantation diagnosis, gene therapy, the study of malignant disease, and others. The benefits, academic and scientific, are enormous. Apart from these benefits are many moral, legal, religious and ethical problems and reservations. Potential sources from which the preembryos may originate may also lead to controversy. Pressure groups in various societies seek to hasten governments into legislation or other means of control. We conducted a Medline search of all pertinent literature since 1980, and the findings are reviewed following. Regulated use of preembryo research is ethically acceptable by most groups in society. Suggestions for regulation are provided.