What should I do with my frozen embryos?

The news that thousands of frozen embryos are to be disposed of at the end of the month, in accordance with a five-year time limit, raises highly emotive issues. Do we regard these embryos as souls on ice, potential human beings with inalienable human rights, or as a cluster of eight cells "less than the size of a full stop", merely a part of reproductive fall- out, no different from - and no more to be regretted than - the thousands of embryos lost naturally each month?

We may feel, vaguely, that they are both - or neither. Most of us, one suspects (and not necessarily the best of us), lack all conviction, while those at the extremes are filled with passionate intensity.

One new question, however, arises out of this: where have all the parents gone? As many as 2,500 embryos will perish because the parents cannot be contacted - which does not mean, of course, that 2,500 couples have lost touch; the figure is closer to 600.

Frozen embryos are a by-product of assisted fertility, harvested from super-activated ovaries and - to put it at its crudest - stored as "spares". Any one couple may have two, three, four or more of them, and they alone can request a five-year extension or consent to "adoption", or to the use of their embryos for research. The people who seek IVF are usually desperate to have babies, so their embryos are surely precious. Why is it, then, that in hundreds of cases efforts by leading clinics to contact these "owners" have been in vain?

"They're like the forgotten embryos," says Mary Sidebotham, a trained midwife and donor recruitment co-ordinator at St Mary's Hospital, Manchester. "We have had the experience at St Mary's of trying to trace people, and it can be very hard. I can't understand how you can just forget. You would think that every time you looked at your child, you would remember that there were a potential two or three brothers or sisters left."

Gillian Mills and her husband, Stephen, certainly don't forget that they have three frozen embryos. After all, they have their son Daniel, 22 months old, to remind them. "Some days," says Gillian, "I look at Daniel's little baby things, and I think about the embryos. I think: 'They're still there.' "

She is one of those who can cut through the ethical debate, so convinced is she, from her own experience, that assisted reproduction adds immeasurably to the sum of human happiness. The choices for her are simple: to have two of those embryos implanted, to try for a second baby, perhaps twins, and to donate the third; or to donate all three.

"I'd love another child, I really would. When I was carrying Daniel, I didn't enjoy the pregnancy at all, I was worried from day one. And then, when he was six weeks premature ... oh, God, it was terrible! I think I could enjoy a second pregnancy, knowing that if things did go wrong I'd be upset, but not as upset as I would have been if I'd lost Daniel. It might not work next time, but at least I'd know I'd tried. My husband says we've got what we want - our lovely son - and to donate all three. I have to decide by September."

She and Stephen would not, then, contemplate disposal? "No way would I do that! I think it's wrong. As far as I'm concerned, that's a life. Why destroy it?"

Gillian is influenced by the fact that she was the recipient of donor eggs. She has a sense of debt to an unknown woman, and to the NHS. "I went on IVF first, and that's when they discovered that I wasn't producing any eggs. I then had to go on another two-year waiting list, so altogether it took eight years. We've been married for 20-odd years, I'll be 40 next year, and if it wasn't for this donor, what would I have done? Now I speak to a lot of people who are on infertility treatment and I think maybe my embryo could help them. Daniel could have another little brother or sister somewhere. I'll never know who gets mine, but at least I'm giving someone else a chance."

A small chance, for sure, but a very real one. And it is the idea of not knowing, conversely, that persuades some couples to request their embryos' disposal. "I do think", says Mary Sidebotham, "that some people won't donate their embryos because they would rather their baby didn't exist than live with the idea that someone, somewhere, might be bringing up their child." For such couples, whether or not they are childless, it may be easier to cope with disposal of the embryos than to live with abiding uncertainty.

Sue Johnson, 37, and her husband, Graham, cannot look at their baby, Polly, without being reminded that they have a frozen embryo. Unlike Gillian, they would not consider donation. They are hoping, anyway, to have the embryo implanted, to try for a brother or sister for Polly. But were they to change their minds, they are quite clear that they would opt to have it destroyed.

"I think you'd feel differently if you didn't have a child," says Sue. "But now that we have Polly, it becomes very, very vivid. Those aren't just embryos, they are potential Pollys, and we wouldn't be happy just to give her away and never to know what sort of life she had."

Polly is their own genetic child; they have not needed a donor. Sue would not feel so shaky about donating her eggs and is considering doing so - her own way of paying something back. "It would only be, genetically, half ours; it wouldn't be the same as the embryo; an embryo is our child."

Gillian and Stephen, Sue and Graham, have been lucky. For less fortunate couples with intractable fertility problems, the long road of assisted reproduction leads to disappointment. One can perhaps see how those for whom all intervention fails and who must come to terms with childlessness might not choose to donate their embryos, to give away, as it were, the child they could not have. But one can see, too, that for other couples a donated embryo could mean the difference between parenthood and lifelong childlessness. It is, in this sense, a unique gift.

When the need for a baby becomes all-consuming, people often cannot see beyond the cycle of treatment, they cannot look to the day when they must make such choices. More fertilised eggs represent more possibilities for implantation: just let one, any one of them, take!

Then, recent concerns, misplaced or not, that invasive procedures such as ICSI (intracytoplasmic sperm injection, in which a single sperm is introduced directly into an egg) carry risks of damage and that frozen embryos might not develop so well - fears that problems may be caused that will not manifest themselves until the child grows to young adulthood - have undoubtedly discouraged a few couples.

"I think that made a lot of people say: 'Well, I'm not having those put back because I have my baby, and I'm very happy, but those embryos are frozen and we'll never know what damage has been caused, so I'll just go for IVF again,' " says Mary Sidebotham.

And, in so doing, maybe, they will abdicate responsibility for the frozen embryos, assuming that decisions will be taken by clinicians, which in law they cannot be.

"They may imagine that they'll just use them for research, or give them to someone else. But they've not actually given permission to do that and legally they have to."

For Mary, who has experience of seeing overjoyed couples with normal, healthy babies who have been born from frozen embryos, this is a great pity. Then, she says, on a more practical level, "A lot of people come to England for private treatment, they go back pregnant and happy, have a baby and lose touch."

There must be an argument for more thorough exchange of information between doctors and those patients who consider cryopreservation. Anyway, anyone contemplating the freezing of their embryos should be aware of the stark choices they will one day face.