"So what would you like - a boy or a girl?"

The minister for public health, Caroline Flint, recently announced a public consultation on changes to the Human Fertilisation and Embryology Act 1990 that would permit ‘family balancing’ - a cosy term for choosing the sex of babies. Miss Flint believes that it is time to debate whether couples should be allowed to have treatment to give them their choice of a boy or a girl, and also to decide how many children of one gender a couple would need to have before being given access to sex selection.

This would be a very considerable easing of the present law, which permits sex selection only in cases where there is a risk of a baby being born with a hereditary disease that only affects one sex, such as haemophilia. The Commons science and technology select committee in March said in a report on assisted reproductive technologies that: "We find no adequate justification for prohibiting the use of sex selection for family balancing."

As usual there have been widely contrasting reactions to this news. John Harris, professor of bioethics at Manchester University was positively enthusiastic: "I welcome the review. If it's not wrong to wish for a bonny, bouncing baby girl, how can it be wrong to use technology to play fairy godmother to ourselves? Sex selection should be a matter of individual choice, and the principle should be that unless palpable harm can be demonstrated, people should be free to make their own choices."

However, David King, the director of Human Genetics Alert, said: "Social sex selection should not be allowed because it turns children into consumer items and allows gender stereotypes to determine who gets born. It will throw the door to designer babies wide open."

The public reaction is likely to be somewhere in between these two extremes. Most people have only a vague awareness of what is happening in scientific research, and there is always a majority view that if science can eliminate nasty things it should be allowed to do so. Thus the public raises little objection to pre-implantation genetic diagnosis (PGD), which is a screening technique used for couples with a family history of serious hereditary conditions that will affect a child from birth, such as muscular dystrophy. The present law allows them to choose embryos that will not be affected. But there are already pressures to extend this technique to screen out embryos for conditions such as some breast cancers that may not develop until late in life or may not even occur at all. Clearly this is just a few steps away from the creation of designer babies, where ALL defects are screened out.

Screening for sex-linked genetic defects is clearly not the same as sex selection, but the technique could be used for both purposes; sex selection is not a distant prospect - it could begin tomorrow. So if a couple have a son and want a daughter, should they not be allowed to have sex selection to get one? If a couple has daughters and the husband wants a son to "carry on his name," should they be allowed to use this technology?

There are strong arguments for saying ‘no’. For example, if parents are desperate for a boy they probably have definite ideas about what a boy should be like, and may be devastated if their son doesn’t conform to their wishes. In such a case the son would certainly have his life blighted through having unrealistic expectations forced on him. In our present celebrity culture parents may seek ‘family balancing’ as a social trend or as a fashionable idea. One of the most discussed topics of sex selection is the possibility of an unbalanced sex ratio in society. We all know about the disastrous effects of meddling with natural procreation in China. Some feminists believe that an uneven sex ratio will result in more humiliation and mistreatment of women, although it has to be said that others think that a reduction in the female population will cause greater competition among men for female partners, making women more valued. (Note that it is always assumed that if sex selection becomes popular most people will want boys.)

In fact the questions about the results of sex selection are unanswerable because it is difficult to imagine living in a society where parents are at liberty to choose the sex of their child. If sex selection became very popular, would the sex imbalances result in laws that required doctors to select both genders in equal numbers, so that nobody had a choice at all? And would the freedom to decide the sex of a baby not very quickly lead to pressure for the ideal baby?