Because the procedure for obtaining eggs for donation is difficult physically, involving superovulation, egg retrieval and IVF, you would expect the financial compensation in payment for egg donation to be greater than for sperm donation -- and so it generally is.

A survey of 51 egg-donation programs by Dr Mark Sauer and Dr Richard Paulson in the US in the mid-1990s showed that 30 of them, or about 60%, used only donors designated and introduced by the recipient couples themselves, implying that there was a personally identified sympathy for the infertility of a close relation on the part of the donors. The donors were usually sisters.

By 2000, however, a most egg donations in the U.S. were commercial arrangements in which the donors were paid from US $2500 to US $5000 or more.

. . . and pregnancy after the menopause

Considerable controversy has arisen from the use of eggs from young women to enable pregnancy in women bwhose own eggs have long been gone.

A commercial clinic in Rome, Italy, has been behind women in their 50s and 60s getting pregnant and becoming mothers. Governments elsewhere have been alarmed enough with this practice to legislate against it -- generally using unfortunately simplistic, even arbitrary, logic.

Intuitively, most of us will be uncomfortable with the notion that women -- particularly just rich women -- can buy the opportunity to get pregnant at any stage of their lives. We can approach (and the popular press has approached) this issue from a number of angles, including the welfare of the intended child, social equity and so on.

But the perspective that to me is the most clarifying has received scant attention, perhaps because it's at once more complicated and less emotional.

The key to me of the acceptability or otherwise of young eggs producing pregnancies for older women is to see the event from the perspective of the person who is going to provide the eggs -- the egg donor.

Many of us are happy, in good circumstances, for a well-informed sister or friend of a woman with early menopause to go through an IVF cycle, including stimulation and follicle aspiration for egg retrieval, out of affection and concern for the unfortunate woman in question.

This can be an acceptable personal freedom to grant the donor, provided we can be sure that no undue or inappropriate coercion has occurred, and that she and the people important to her are properly informed and counseled, so that they won't end up suffering from regret about their decision.

But can the same ever be true for a woman who is past her own normal menopause asking this of a young stranger?

More often than not, such a woman's own friends or sisters will themselves be at or beyond the menopause too, so for this purpose they won't be useful to her. Her relations, if they're to be young enough to be helpful this way, will most likely be in some kind of dependent relationship, and ought to be disqualified on these grounds (for sure, I would not be a party to a mother asking for egg donation from her daughter).

Indeed, the only motive that remains viable is commercial: the payment of money to the donor by the recipient, directly or indirectly, with the doctor as the commissioning broker.

But this too is awkward. The average age of egg donors in some U.S. egg donor programs is just 21. This means that fully half of the donors are still teenagers.