It has been suggested that if the demand for human gametes and embryos, for either treatment or for research, increased, there could be a risk of commercial exploitation and of an export and import trade. We would see this as undesirable. On the other hand we can foresee situations where the supply of human gametes or embryos might reasonably involve some commercial transaction, for example if a licensed semen bank was asked to supply specimens to a distant part of the country which would involve them in considerable costs of transportation, we see no reason why they should not seek reimbursement of expenses. Thus a complete prohibition on the purchase or sale of such material would be inappropriate.