Presentations and discussions focused on questions related to six major themes. These included the existing and emerging methods for including biological measures in research, the validity of the research on which various biological measures might be selected, and the link between non-human primate and human studies in this area. Other issues focused on the equipment, techniques, and costs of collecting data on androgens, neurotransmitters, electrical potentials of the brain, deoxyribonucleic acid polymorphisms, and other biological variables; biological measures associated with prosocial behavior and development; and appropriate pilot studies for the next two years. Discussion papers, reference lists, and list of participants