The immediate reaction of busty model, Jordan, to being told that her baby son, Harvey, is blind, was to question whether her party-filled pregnancy could have caused the failure of the optic nerves to develop. There is a possibility that excessive drinking or using cocaine during the vital development period in the earliest weeks of pregnancy could cause the optic nerve hypoplasia from which Harvey suffers. It is much more

likely, however, to be the result of random chance.

''Saying that babies who suffer from the condition have been damaged by alcohol or drugs is like saying that everyone who breaks a leg must have been drunk,'' is how Jane McLaughlan of the Royal National Institute for the Blind put the probability into perspective.

Normally the optic nerve, the pathway for transmitting information from eye to brain contains about 1.2 million fibres. In optic nerve hypoplasia that number is reduced by between 10% and 90%. The effects vary from minor problems to having no vision other than a perception of light, and ONH is also likely to occur with other defects of brain development linked to the pituitary gland, which can result in growth problems, hormonal imbalances, and difficulties in regulating temperature.

Because it is the result of failure of formation of the fibres in the womb or the death of nerve fibres at a later stage of pregnancy, there is no treatment that can reverse the abnormalities, nor will the condition worsen.

Doctors do not know why the nerve fibres fail to develop. There does not appear to be a major genetic element. The condition is rare, but tends to occur more in younger mothers.

Specialists at Moorfields Eye Hospital in London have reportedly reassured Jordan, whose real name is Katie Price, that Harvey's condition was the result of random chance rather than her partying lifestyle, which included a failure to give up alcohol during pregnancy.

The surgically-enhanced topless model, currently en route to Hugh Hefner's Playboy mansion in Los Angeles to promote a series of nude photographs for the magazine taken before her pregnancy - and a possible appointment with US eye surgeons - was frequently criticised for drinking during her pregnancy. In March, only two months before the baby was born on May 27, she was spotted swigging champagne at a premiere for Ali G at the Mayfair Club before getting into a scuffle with another woman at a nightclub. ''I've only got seven weeks of freedom left and I intend to make the most of them,'' she protested to critics.

That was only a day after she was warned that she could be putting her unborn baby at risk by using a sunbed. Prompted by reports of her using sunbeds regularly, the Royal College of Midwives urged her not to, warning: ''There is some evidence that overheating while pregnant could damage the baby. It's possible that it could cause a stillbirth.''

In fact, Harvey weighed in at a sturdy 8lb 7oz after a natural labour, which was induced because he was 12 days overdue. His arrival was not broadcast live on the internet as his mother had originally planned on a pay-per-view basis, not, heaven forfend, to make money but ''to help reduce the fear of childbirth'' for other new mothers.

This topsy-turvy celebrity world in which Jordan's only assets, her size 34FF breasts, are not used for their natural purpose - five-week-old Harvey seems to have been bottle-fed by his grandmother as often as by his mother - but to gain her employment as a nude model or an attraction to open motor shows, has now been visited by genuine tragedy.

The lack of knowledge of the cause of optical nerve hypoplasia leaves a question mark over whether or not Jordan's lifestyle might have been a contributory factor to her son's disability. With the emergence of a generation of young women who consume more alcohol than any previous one - due to a change in the way it is sold and marketed, and an ability to postpone motherhood - there is rising concern about the effects of alcohol on the foetus.

Babies born with foetal alcohol syndrome have small heads and abnormal facial features including small eyes, flattened cheekbones, and lack of definition between nose and lip as well as central nervous system defects including learning disabilities and hearing and vision problems.

In the US anxiety about FAS, and a genuine difficulty in setting a safe limit for alcohol consumption in pregnancy, has led to a vigilante-like policing of visibly pregnant women in public places, to the extent that anyone who dares sip a glass of wine or light a cigarette while displaying a bump has to be prepared to imbibe a dose of vitriol with it.

Ask Kate Moss. The extent to which the famously waif-like frame is dependent on an unhealthy nicotine habit has become clear during a pregnancy in which she has been spotted lighting up during the interval at the theatre and while driving through London in her Mercedes. The incident which brought the wrath of the anti-smoking campaigners on her diminutive, but expanding, frame was when she swore at an attendant at the National Portrait Gallery who asked her to stub out her cigarette. That anti-authoritarian act inspired Forest, a group which campaigns against restrictions on smoking, to nominate her as smoker of the year.

Although she quickly put out a statement saying that she was following doctor's orders and cutting down drastically in an attempt to give up smoking completely, Forest's attempt to capitalise on her fame brought Ash (Action on Smoking and Health) into the fray, calling them irresponsible for applauding Moss's smoking during pregnancy. The facts, of course, are on their side: women who smoke are more likely to have a miscarriage and their babies are more at risk from cot death. Smoking slows down the baby's development in the womb and increases the need for special care after birth.

That so many women find it impossible to give up despite the well-established dangers and a natural desire to do the best they can for their child, raises the question of why so many young women have become so addicted despite the concerted efforts of health educationists for a generation. One factor is that a still enviably thin though evidently pregnant model is a more powerful message for some than the acknowledged but ignorable facts.

Ask Emma Beal. The pregnant girlfriend of Ken Livingstone, the mayor of London, was unknown until she was involved in a spat with the mayor, sparked by her decision to accept a cigarette at a party to celebrate her sister's 40th birthday. In fact, she had given up smoking during her pregnancy and the party puff was apparently an unusual lapse. In the way of these things, the consequences were unforeseen. Her partner's reaction to this threat to his unborn child resulted in a scuffle which was reported as a drunken brawl.

On one level: tabloid morality, Jordan's Playboy pics, it boils down to the latest take on that old-as-mankind dichotomy between madonna and whore. On another, in an age young women's role models are the women whose impossibly glamorous images dominate the living room and whose Technicolor lives dominate the magazines and newspapers, the good-time girls provide an illusion of liberty more attractive than sober responsibility. Pregnancy isn't life-changing. Motherhood is. It's a lesson that only life can teach and sometimes it's a tough one.

Demi Moore's famously nude pregnant pose for Vanity Fair just a month before giving birth was the starting pistol for any publicity-seeking model/singer/TV presenter fearing pregnancy would keep her out of the limelight for several months to present her bulging tum between low-cut trousers and short-cut top. The message is that pregnancy is something to celebrate - and so it is.

Yet the Texas vocalist Sharleen

Spiteri, who has been taking motherhood very seriously, having announced before becoming pregnant that she planned to take two years out of her touring schedule, was criticised for ''looking little better than a bag lady'' while wearing hat scarf, jacket, and cargo pants.

Yet somewhere between the in-your-face midriffs and the dull tent-like garments of old is a positive image for 21st-century women - and their future children. It's probably not that American phenomenon in danger of being imported along with the pregnancy police if non-pregnant sisters and friends follow Stella McCartney's lead. Her ''baby shower'' party for her sister Mary included Sharleen Spiteri, Kate Moss, and actress Sadie Frost, all expectant mums, plus other celebrity friends. Refreshments included wine and champagne by the ice-bucket, but Ms Frost, at least, has a track record of abstinence. The only time alcohol has featured during her pregnancy is when she has taken gifts of champagne home instead of drinking them.

There's always the other side of the coin. The exercise freaks have also come in for their fair share of criticism. TV presenter Gail Porter, pushing the pedals on an exercise bike at her local gym, has been warned not to overdo it, but cycling along with swimming and walking generally gets a seal of approval from the medics, while Pilates, the new stretching craze, is seen as a gentle but effective way of keeping fit and regaining shape after birth, as evidenced by Liz Hurley and Davina McCall. Madonna and Zoe Ball, however, have remained faithful to the yoga mantra.

The RNIB offers support to people with serious sight problems, who include 22,000 children under 16 throughout the UK. Their helpline is 0845 766 9999.

pregnancy's pitfalls

Kate Moss (left) brought the wrath of the

anti-smoking campaigners on her diminutive, but expanding, frame

when she swore at an attendant at the National Portrait Gallery who asked her to stub out her cigarette. That anti-authoritarian act inspired Forest, a group which campaigns against restrictions on smoking, to nominate her as smoker of the year.

Emma Beal (centre), the pregnant girlfriend of Ken Livingstone, the mayor of London. Her decision to accept a cigarette at a party to celebrate her sister's 40th birthday sparked an argument over harm to the baby. In fact, she had given up smoking during her pregnancy and the party puff was apparently an unusual lapse.

Sharleen Spiteri, the Texas vocalist (right), has been taking motherhood very seriously, but was criticised for ''looking little better than a bag lady'' while muffled in hat scarf, jacket, and cargo pants.