Can it be a crime for a woman to drink too much while she's pregnant? It already is in the US, where pregnant women can be imprisoned for having babies with foetal alcohol syndrome (FAS). But it would set a precedent if it were determined criminal here, in a test case soon to be brought by a local authority before the court of appeal.

The Criminal Injuries Compensation Authority is contesting the local authority's claim, and it has already won the backing of one judge who ruled that a foetus can't have personhood, and therefore can't have a crime committed against it.

Neil Sugarman, from GLP Solicitors, is representing the local authority in an appeal: his argument is that the child was poisoned in utero, which is an act of violence whose costs, metaphorical and, crucially, literal will be levied for a lifetime. He explained: "The local authorities won't provide the medical care and treatments these kids need."

I suggested that these were wooden dollars – his firm wins, the money is recouped from one government department (CICA), given to another (the local authority) to pay a third (whoever is providing social care). "It's not wooden dollars," he said, "because at the end of the day, this is taxpayers' money." As, of course, it would be if the local authority paid for it.

In the end, he conceded: "Had there been governmental recognition of the fact that children damaged by alcohol and drugs need rapid and long-term access to specialist services, we probably wouldn't be having this argument." But there isn't, so let's turn it into a crime; layer in solicitors, liability estimates and all the bureaucratic apparatus this entails. It will be more expensive to a fiendish degree, but who cares? At least we'll have found someone to blame. You can't put a price on satisfaction like that.

So what happens if the local authority wins? Since a violent act has been committed, doesn't that make the mother criminal? Would she be prosecuted? Would she be sentenced? Would they have to balance the sentence against the fact the baby had been removed? Would the removal of a child thereby become a punishment that could be tariffed in law? What does this mean for abortion? If you can commit a crime against a foetus, it must, in the first instance, be criminal to terminate it, surely?

If this case actually passed, for the sake of deciding who would pay for the care of a minuscule number of disabled children, the legal status of the pregnant and the pre-pregnant – all fertile women – would be profoundly changed.

This is territory nobody would touch, were it not for the rabid overstatement of the incidence of foetal damage as a result of alcohol.

The figure used by the Department of Health is that 7,000 babies are born annually somewhere on the spectrum of foetal alcohol disorder (FASD). These are not babies with FAS, which is profound and very easily diagnosed. Foetal alcohol spectrum disorder, however, includes conditions whose symptoms are extremely complicated and subjective, and whose genesis has never been established and is highly unlikely to be any single source. This hasn't stopped the pressure group Nofas estimating one in a hundred babies are born with FASD. It arrived at the 7,000 total by estimating how much women drink, associating that with conditions it has no proof are alcohol related, and dividing the birth rate by 100.

Dr Ellie Lee, sociologist and author of a paper, Policing Pregnancy (included in her book Parenting Culture Studies), says: "It's just a claim they make, it bears no relation to any collected statistics about birth defects. If you took this seriously, more than half of babies born with disabilities (approximately 14,000 a year) would be FAS babies. And the majority of disabled babies don't even have brain damage."

Some measures are more kosher than others; the mothers of children with autism and ADHD (attention deficit hyperactivity disorder) are sometimes quizzed about alcohol use, and a link is found that way. While that falls a long way short of proof, it's nothing on Susan Fleisher, a Nofas representative who once said to me: "Of course, the saddest cases of FASD are the ones that aren't diagnosed. They often end up committing suicide, because they've struggled with this condition all their lives." "How do you know they had FASD, though, if they were never diagnosed?" "Well, they committed suicide!"

This is all based on the belief in a dose-response effect: heavy drinking causes heavy disability, ergo light drinking must cause light disability. We have no evidence at all for this; indeed, there's some emergent evidence that the children of light-to-moderate drinkers do better, cognitively, than children of teetotallers.

Babies with FAS, meanwhile, are counted among hospital episode statistics and are very rare – between 2002/3 and 2007/8, there were 987 cases. There was an upward trend, and the suggestion of under-reporting. However, the highest rate was 1.67 per 100,000 (in the north west ), or 0.0016%.

This matters because sustained misinformation has turned a very serious, tragic, low-incidence side-effect of addiction into the myth of 7,000 women a year who don't give a toss. As Sugarman puts it: "The birth mother has been warned about the dangers, and she's just said, 'I don't care what happens, I'm going to do what I want.'"

It matters because we can all, in our right minds, understand that alcoholic mothers need intensive support. We all know that taking a moral stance has never, in the history of addiction, had the desired result. We can all recognise the need to balance the adult's rights and the child's. To be pregnant and alcoholic is not a situation you would wish on anyone; it calls for sophistication, subtlety, persistence, expertise and kindness. Trying to solve it in a court is like trying to crack a code with an attack dog.

Twitter: @zoesqwilliams

• This article was amended on 6 February 2014 to clarify the status of Ellie Lee's paper, Policing Pregnancy, which is not the book of the same name by Sheena Meredith.