The present acute shortage of eggs for donation cannot be overcome unless adequate guidelines are set to alleviate the anxieties regarding payments, in cash or kind, to donors. The current Human Fertilisation and Embryology Authority (HFEA) guidelines do not allow direct payment to donors but accept the provision of lower cost or free in vitro fertilization (IVF) treatment to women in recognition of oocyte donation to anonymous recipients. Egg-sharing achieved in this way enables two infertile couples to benefit from a single surgical procedure. However, the practical guidelines related to this approach are ill-defined at the present time leading to some justifiable uncertainty. A pilot study was therefore undertaken in order to establish the place of egg-sharing in an assisted conception programme. The current HFEA guidelines on medical screening of patients, counselling, age and rigid anonymity between the donor and recipient were followed. The study involved 55 women (25 donors and 30 recipients) in 73 treatment cycles involving fresh and frozen-thawed embryos. Donors were previous IVF patients who, regardless of their ability to pay, shared their eggs equally with matched anonymous recipients. They paid only for their consultations and tests right up to the point of being matched with a recipient. The sole recipient paid the cost applicable in egg donation of a single egg collection, although both received embryo transfers. The results indicate that although the recipients were older than the donors (41.4 +/- 0.9 versus 31.6 +/- 0.5 years), and there was no difference in the mean number of eggs allocated, the percentage fertilization rates, or the mean number of embryos transferred, there were more births per patient amongst recipients than amongst donors (30 versus 20%). We conclude that providing the donors are selected carefully, this scheme whereby a sub-fertile donor helps a sub-fertile recipient is a very constructive way of solving the problem of the shortage of eggs for donation. There are also the advantages of including a group of women who would otherwise be denied treatment. Problems related to 'patient coercion' can, in our view, be fully overcome by the application of strict common-sense safeguards. The ideal of pure altruism is not without its medical and moral risk. The success of egg-sharing depends on shared interests and a degree of altruism between the donor, the recipient and the centre. The current HFEA guidelines should be applauded for enabling a highly effective concept of mutual help to develop.