Some women donate them, some trade them for IVF, some sell them. But there still aren't enough, and demand is increasing. Mary Braid investigates a shadowy trade

Laura Witjens gave her eggs to another woman. To her, and other altruistic donors, an egg is one of the greatest gifts one woman can ever give to another. "I feel that helping another woman to have children is one of the best things I have ever done," says Witjens, 41. She made her decision after seeing a television programme about the shortage of eggs in the UK and while she was still basking in the happiness of giving birth to twins.

"It was a no-brainer for me. I had had my family, and every month my eggs were just flushing through my system. I have no hang- ups about any offspring that may have resulted from my donation making contact with me later in life. I'm fine with that.

Witjens, originally from Holland, is tall, good-looking and blonde. She could have made a small fortune selling her eggs abroad. In Europe it is illegal to buy eggs, but in Spain private clinics offer "donors" "compensation" of €900 (£620), creating a thriving market among students and immigrants. But campaigners for tighter regulation of the fertility industry argue that the poor and vulnerable are being lured in without understanding the risks to their physical health of repeated donations and repeated hormone injections to stimulate egg production.

In America, the market runs riot through the pain of infertility. Couples in search of donors with Ivy League grades, blond Wasp looks and cheer- leader smiles pay tens of thousands of dollars for eggs. The web is littered with sites featuring cute US college students with eggs for sale.

The dark underbelly of the billion-dollar US fertility industry was exposed two years ago by Julia Derek, a Swedish student studying in the US, who made tens of thousands of dollars in nine egg "donations" to private US clinics. In Confessions of a Serial Egg Donor, Derek described how donating eggs to fund her studies damaged her ovaries and left her an emotional wreck. Would "some poor girl have to die" before US clinics are properly regulated, she asked.

But at least in Spain and the US there is some regulation. In other parts of the world, a seedy trade is emerging in which poor women risk their lives, often for a pittance and for the benefit of richer women.

Romanian lawyer Dr George Magureanu complained in his own country and at the European parliament last year about the treatment of two young women - Alina, 19, and Raluca, 24 - who gave their eggs to the Globalart Clinic in Bucharest in return for "compensation" payments of £140. The women, who worked in a mattress factory for £57 a month, claim that the clinic, which had an egg-sharing arrangement with the private Bridge Centre in London, shut its doors on them when they developed health problems after egg donation.

Dame Suzi Leather, chair of the Human Fertilisation and Embryology Authority, said last week, "In some cases, the recruitment of egg donors occurs under conditions that we may consider unacceptable, with women coerced by unscrupulous individuals or organisations to sell or give their eggs." The abuses were worst in countries with poor human rights records.

Eggs are in short supply across the developed world where women, with more life choices than their mothers ever had, often delay motherhood beyond the natural life of their own eggs. The UK relies on altruistic donors and egg-sharers - women who give half their eggs in return for IVF treatment - and has chosen, on ethical and moral grounds, not to let hard cash be the solution to its shortage. But not everyone agrees that women who share eggs in return for free or cut-price IVF treatment are entirely uncoerced or indeed unpaid.

Meanwhile, the internet, cheap flights and desperation herald the age of "fertility tourism". Internet fertility sites are dominated by women's reports of successful and cheap trips to clinics from everywhere from Kiev to Cyprus. Spanish clinics are particularly popular, not least because they boast higher "live" birth rates from egg donation than British clinics.

"The private Spanish clinics target students and 'good donors' among Eastern European immigrants who produce large number of eggs," says Spanish law professor Itziar Alkorta-Idiakez, a campaigner for better regulation of reproduction technology.

"The 'secret' of their success in live births - 50 per cent of egg donation procedures compared to 30 per cent in Britain - is that they use eggs from 20- to 25-year- old women and not the eggs of IVF-users who are considered too old or who have problems.

"Increasing demand means clinics are employing increasingly aggressive strategies to recruit donors. Recruiting campaigns take place mainly at universities and educational centres." Though the altruistic element in donation is emphasised in the campaigns, they are targeted at poor women. A British nurse working in a Spanish clinic recently told a British newspaper that Spanish women with fair colouring are in particularly high demand: "We've been known to chase blonde blue-eyed girls down the bus," she said.

For UK women who go to Spain, Kiev, Greece and numerous other new fertility tourist destinations, the right of any offspring to know the donor's identity tends to disappear when fertilised donor eggs are implanted overseas. "Clinics who send women overseas for egg implantation are acting against the spirit of the law in the UK," says Olivia Montuschi of the Donor Conception Network, which represents families with children conceived through gamete donation.

Professor Gedis Grudzinskas, director of the private London Bridge Fertility Centre, claims that altruism is part of a Romanian egg donor's motivation.

"That's absolute rubbish - money is a more obvious motivator of poor women," says Montuschi.

In Spain, there have been no horror stories about standards. Spanish clinics enjoy a good reputation and are not involved in egg-sharing schemes with UK clinics. Until the surge in interest from the UK, their main foreign customers were from Germany and Italy, where egg donation is banned.

Feelings in the future about giving away her eggs, don't seem to have entered the thinking of young donor, Noelia Perez, 26, a student from the Basque region.

"I found out about egg donation when my flatmate, who is a journalist, went to interview the director of a private clinic," she told a Spanish newspaper. "I was astonished at the money you could earn. It was a very attractive opportunity. If you think that you can donate eggs every three months, that means you can earn €3,600 (£2,500) a year."

For this, Perez has had to undergo numerous tests to confirm she is disease- free and has been injected with hormones to stimulate her egg production. Then she had an operation under local anaesthetic to have the eggs extracted.

Professor Alkorta-Idiakez says demand for such women is growing to satisfy an expanding need both at home and abroad.

For Dr Elizabeth Pease, consultant in reproductive medicine at St Mary's NHS Hospital in Manchester, what currently motivates women to give eggs - even in the UK - is far from straight forward. Last year, according to the Human Fertilisation and Embryology Authority (HFEA), at least 700 women donated eggs in the UK (less than half of what is needed) with a 50:50 split between altruistic givers (mostly friends and relatives of infertile women with a few unrelated altruists like Witjens) and egg-sharers.

Egg-sharing isn't done at St Mary's, because when the NHS is funding limited treatment - often just one IVF cycle - "sharing eggs is not in a woman's interest". But Dr Pease and her colleagues also have ethical concerns about the practice that centre on the idea of egg sharing as voluntary and free. "The question you have to ask egg-sharers is, would they have donated their eggs if they could have afforded to pay for their own fertility treatment," she says.

For Dr Pease, egg-sharing plays on the desperation of women who cannot get treatment on the NHS and end up in private clinics. What option is left, she suggests, but to sell - in barter if not hard cash terms - their eggs. "There is also a chance that the egg-sharer's IVF treatment will not be successful, while the woman who receives half her eggs may go on to have a baby," she says. "How will the woman who egg-shares feel about that?"

This point is more of an issue since a change in UK legislation last year removed the right to anonymity from donors of eggs and sperm and gave people conceived through donated gametes the right to know the identity of their biological parent. Eighteen years after an egg or sperm donation, the person created from that donation could be standing on the donor's doorstep - and looking just like them. That has implications not only for donors, but also for spouses, half-siblings, the extended family, and the very notion of family itself.

Despite this, Jane Cosgrove, 39, who gave eggs three times in return for free IVF treatment at the private Lister Hospital in London, sees egg-sharing as an entirely straightforward arrangement. To her it boils down to one fact. Without egg-sharing, she could never have afforded the IVF treatment that finally produced her daughter Kira, four.

"I was so grateful for Kira that I went back to the Lister after she was born and donated my eggs again for free," she says. Having fertility problems, she says, made her so sensitive to the pain of other infertile women that altruism became part of her egg sharing motivation.

Was it really that straightforward, emotionally and psychologically? On her first two failed IVF attempts, did Cosgrove not feel jealous that another women might be happily pregnant with her eggs?

"When it failed the first time, I did think that some other woman had half my eggs, but you have to put that right out of your mind," she says. "Giving my eggs was like giving blood to me. I make a firm distinction between eggs and babies."

She has no desire to know whether her eggs did create children. "I just hope they did because I'd like someone to be as happy on Mother's Day as I am now I have Kira," she says.

Suzi Leather has called for governments, international organisations, doctors and patients to protect all involved in egg donation - including the donor. With the shortage of eggs in the UK inextricably linked with the rise of the overseas egg trade, what might we do here to prevent the exploitation of women abroad?

Witjens, now chair of the National Gamete Donation Trust, which promotes altruistic egg donation, thinks more altruism is the answer. "It's not for everyone, and donors have to be counselled because donation is something that can't be undone," she says. "Altruism can be encouraged in the UK, but it will take more funding than we have."

Dr Sam Abdullah, director of the Lister, agrees. He isn't against paying donors in principle but says that majority British opinion is against that and that he is uncomfortable with an international egg trade that currently "pays tuppence" to women in poor countries for their eggs. "I think there is a reservoir of benevolence in the UK that has not been fully tapped," he says.

But Professor Grudzinskas argues that the long-term solution is to pay donors, and that egg-sharing is already payment in kind. "Altruism hasn't worked but the financial incentive does," he says.

The other solution would be for more women to accept infertility - a possibility that seems to have absolutely no legs at all.