Just imagine if James Kelly had won...

Wake up, says Ann Treneman. A double whammy of men's rights and foetal rights could soon push women's rights out of the window

Sarah awoke with a thumping headache - too much champagne again - and went downstairs to get a paracetamol. Instead, she found a glowering husband. "I'm furious you drank so much last night. What if you're pregnant? Think of the foetus, for once. We agreed - no drinking," he said, snatching the pills. "And no drugs! I warn you, if you keep this up, we'll end up in court and a judge will be telling you the same thing."

Sarah's case may be a fiction but do not dismiss it as pure fantasy. Many people may have thought the case of James Kelly - the Fife roofer who tried to stop his wife's abortion - was about fathers' rights. But it was also about foetal rights - and it is the latter which is the bigger issue. "There is no doubt that we are paying more attention to the foetus these days," says Sheila McLean, professor of law and ethics in medicine at Glasgow University. "But if we did start developing a theory of foetal rights it really would mean a woman would have to live her whole life as if she were pregnant."

The ultimate foetal right would be the right to life, but there are many lesser ones: the right not to feel pain, for example, or to a drug-free existence, or to medical care. Each necessarily impinges on the rights of the woman. Those who think that it couldn't happen here should cross the Atlantic and watch a pregnant woman ask a bartender for a Bloody Mary. It might be more than his job's worth: the answer might be polite but it also might be no.

"Five years ago, people said this would never happen. It was the doomsday scenario," says Aminatta Forna, who is writing a book on the politics of motherhood. "Now we have women being arrested for taking prescription drugs such as Valium, for drinking alcohol in a pregnancy. There are signs in every American bar saying if you are pregnant, do not drink."

America did not follow the Kelly case, but we all did. James Kelly decided not to take his attempt to stop his wife's abortion to the House of Lords, but it had all the marks of a classic abortion soap opera. Those who took Lynne Kelly's side may think everything has returned to normal. She is back in control of her pregnancy, her body, her life. But that is not the case.

Legal experts believe this case was heard because it combined the idea of foetal and father's rights and crucially that it questioned whether the doctor responsible had made the right decision to allow the abortion. It is the kind of the thing the 1967 Abortion Act allows for - abortion is not available on request and relies on medical judgement - and this has alarmed the Abortion Law Reform Association. "We are very concerned that cases like this could keep being brought by vindictive partners to harass and delay women who choose to have an abortion." The association is seeking an MP to sponsor a private member's bill for abortion on request.

The power of the idea of foetal rights is that it is at the heart of the abortion issue but is also much wider. It encompasses everything from a woman's behaviour during pregnancy to her decisions surrounding the birth (whether to have a Caesarean, for example), surrogacy, infertility treatments, foetal surgery and much more. "It keeps coming up because it is involved in so many things," says McLean.

Anti-abortion groups in Britain remain attached to their main issue, but they are quite keen on the idea that the foetus has the right to be called a baby. "Do not call it a foetus! It is a child," said Jack Scarisbrick of Life. Other terms in use are "pre-born child" and "foetal personhood". So what would a world of "foetal personhood" be like? What if James Kelly had won and the foetus had been declared to have rights? Catherine Francoise of the Society for the Protection of Unborn Children, is careful to note that she could not support paternal rights any more than maternal ones. But she liked the idea of foetal rights. Her picture is one of a society transformed by having children at its centre. There would be less violence, more breastfeeding, more childcare, more adoption, less selfishness and more compassion.

If you ask the same question in America, you would get another answer. There, the US anti-abortion movement is avidly following many cases that have nothing to do with abortion but everything to do with the rights of a foetus. These involve scores of women imprisoned on charges such as trafficking drugs to a minor (through the umbilical cord) or under the child endangerment laws. "The pro-choice groups that are more legally minded do understand the connection," says Andrea Miller of the New York Centre for Reproductive Law and Policy. "They know that if they develop laws that grant increased rights to the foetus then you can undermine the laws that enable pregnant women to make choices about their medical care during pregnancy. It is not just about abortion but things like women being forced to have Caesareans."

It is not for the want of trying that foetal rights have yet to be officially recognised in law and one case in South Carolina remains particularly worrying. It involves a woman named Cornelia Whitner who gave birth in 1992 to a healthy baby who tested positive for cocaine. She was convicted of criminal child neglect and served 19 months in jail but her case continues on appeal. Her lawyer, Lynn Paltrow, is scathing of the most recent move to uphold the conviction: "There are not enough cells in South Carolina to hold the pregnant women who have drug problems, smoke cigarettes, fail to take prenatal vitamins, or decide to go to work despite their doctor's advice to stay in bed - who could be guilty of the crime of child neglect as a result of this ruling."

Ann Furedi at the Birth Control Trust in London thinks it is inevitable that, because of medical advances, we are thinking of foetuses in a different way. "You can see it now, and it looks like a baby," she says. "You may feel compassion towards it. But you can feel compassion without giving it rights." When I ask Furedi about the James Kelly case, she refers me to a similar case from Quebec in 1989. Jean-Guy Tremblay did not want his estranged girlfriend Chantal Daigle to have an abortion and the highest court in Quebec agreed with him. "The rule of nature is that pregnancy must lead to birth," the judges said. Jean-Guy was overjoyed and spoke of starting a new life with his girlfriend and their baby. Chantal had other ideas and took matters into her own hands. "Even when the right has been granted in law - as in the Quebec case - it is impossible to exercise it in practice. In this case, the woman just crossed into another state and had the abortion anyway," she said. "At the end of the day it is women who are pregnant and they will go to great lengths to carry out their decision." Of course, the decision to buy a drink in a public place could be another matter entirely.