A review of research on the effects of drinking during pregnancy has been launched as evidence mounts that even small amounts of alcohol can damage an unborn baby.
Results of the Government's study, expected early next year, could change the advice given to pregnant women that a couple of small drinks a week is a safe drinking level.
With teenage girls overhauling boys in their drinking habits and binge drinking commonplace in young women, concern is growing over the consequences for the next generation.
Full-blown foetal alcohol syndrome (FAS) causes a range of problems including facial abnormalities and mental impairment and affects one in 1,000 babies, say American researchers.
But the more subtle, foetal alcohol spectrum disorder (FASD) may pose a greater problem. It is 10 times more common but "massively" under-recognised and under-diagnosed, say doctors.
The guidelines in Britain are that pregnant women can drink one or two units, equivalent to one or two small glasses of wine or single measures of spirit, once or twice a week. But advice in America and Canada is now to avoid drinking at all.
Dr Fiona Adshead, the deputy chief medical officer for England, said: "It is vital that public health messages are based on sound evidence.
"That is why we have commissioned a research exercise on the effects of alcohol on developing foetuses.
"This will review the available evidence on the effects of low-level alcohol consumption during pregnancy."
In Britain's Streets of Booze, a documentary on BBC1 each morning this week, Dr Adshead says pregnant women should always avoid getting drunk but that the modest drinking advice would change if the evidence showed that the guidelines were out of date or no longer sustainable.
A survey by the Department of Health in 2002 found that 61 per cent of women reported drinking during pregnancy.
Dr Raja Mukherjee, a psychiatrist and specialist in FASD at St George's Hospital, south London, who deals with patients who were damaged by their mother's drinking, said that he recommends not drinking at all in pregnancy if a woman can avoid it.
"There have been very few studies in the UK and it is hard to give a figure for the prevalence of foetal alcohol spectrum disorder," he said. "I suspect it is massively under-recognised."
Alcohol affects the front parts of the brain and Dr Mukherjee believes that the brain of the foetus is more likely to be damaged when a woman drinks regularly.
"The brain might be able to compensate for one hit, but begins to sustain damage when the same area is hit repeatedly," he said.
Subniv Babuta, the BBC programme's producer, said: "FASD and its effects are not widely known in this country so it is important that awareness is raised."
Full FAS is characterised by small babies, malformed faces or bones, defects of the heart and other organs and learning disabilities.
FASD children would fail to reach their full potential. The babies might be born small, and stay small, might develop more slowly than average and not sleep well.
A 20-year-old with FAS would have the emotional maturity of a six-year-old.