Today the media have picked up on claims that the violence on Britain’s streets is a result of women consuming alcohol while pregnant. The story seems to have started with Scotland’s chief medical officer, Dr Harry Burns, reporting the connection to MSPs.

Pre-natal exposure to alcohol is thought to be linked to a wide range of physical and mental defects, including growth deficiency, learning difficulties, epilepsy, and (at a lower level) poor memory and general clumsiness. Children exposed to alcohol in the womb are even reported to have distinctive facial features, narrow eyes and thin upper lips. The name for these phenomena is Foetal Alcohol Spectrum Disorders (FASDs).

The idea that alcohol exposure damages unborn children is perfectly plausible; after all, it clearly damages adults. There’s still a little work to be done to show that alcohol consumption during pregnancy is a significant cause of violent behaviour on the streets of Britain, however, and certainly not enough in the media reports to do so.

The first thing it would be useful to know is whether the explanation being offered is sufficiently powerful. What proportion of pregnant women drink sufficient quantities of alcohol to cause FASDs? What proportion of children whose mothers drink that much alcohol display violent behaviour? How does this compare to the proportion of children whose mothers don’t drink that much alcohol who display violent behaviour?

Without knowing these things, we can’t know how much violent behaviour could be attributed to FASDs if the claim of a causal link were accepted, so can’t assess its importance as a possible cause of anti-social behaviour.

No doubt at least some of this information is out there (even if it didn’t make it into the media reports). However, there was a slightly concerning comment made in The Herald that the only large study of the prevalence of FASDs was in Italy. For a start, Italian drinking habits are rather different to those in Britain, so there has to be some doubt as to whether Italian findings are applicable here. The lack of corroborative studies also raises a doubt as to whether the connection is as well understood as the reports first made it seem.

Before questioning the significance of FASDs as a cause of violence, however, we should question whether they are a cause of violence at all. Assuming that a correlation between pregnant women drinking and their children tending towards violence has been found, how else might this correlation be explained?

One possible explanation would be that women with a disregard for authority are both (a) more likely to disregard medical advice not to drink while pregnant, and (b) more likely to rear children with a disregard for authority (and so with anti-social tendencies). In that case, a mother drinking while pregnant wouldn’t cause her child to be violent; rather, the mother’s drinking and the child’s violence would share a common cause: the mother’s disregard for authority.

There are other theories that could explain the data too. Perhaps living in a rough neighbourhood tends to drive women to drink and to draw children into gangs. Perhaps children who can steal alcohol from their parents are more likely to get drunk and so get involved in fights. Etc, etc.

Of course, there’s a chance that the claimed connection is real and we’re experiencing social problems in Britain because of pregnant women drinking. There’s also a chance that the scientific community has good reason to believe in this connection.

However, the evidence made available in the national press doesn’t show that there’s a correlation between pre-natal alcohol exposure and violent tendencies in this country, doesn’t show that the best explanation of such a correlation would be that pre-natal alcohol exposure causes violent tendencies, and doesn’t show that pre-natal alcohol exposure causing violent tendencies would explain the levels on violence on Britain’s streets.

For these reasons, the information presented in the media falls well short of demonstrating the connection between drinking and violence that is claimed.