Recent research has found that a mother's consumption of as little as one drink a week may affect a child's brain development, cognitive function and behaviour, and facial shape, while for decades, public health campaigns have repeatedly said that there's no safe amount of alcohol for mums to drink while pregnant.
The scientific consensus seems pretty clear – that prenatal alcohol exposure can cause a variety of problems (although some questions remain around the precise risk of light compared to heavy drinking, for example). Potential harms include neurodevelopmental impairments as well as particular facial features most commonly associated with foetal alcohol spectrum disorders (FASD), but also behavioural, cognitive
But as the risks of maternal alcohol consumption have become better-documented, another potential contributing factor to FASD has remained largely overlooked: how much the father drinks. Research on fertility and reproduction "has been so woman-focused, so maternal centric, that we've not really done our due diligence on the male side", says Michael Golding, a developmental physiologist at Texas A&M University who researches alcohol exposure and foetal development.
Yet researchers like Golding have suspected a paternal role for a long time. "For years now, we've been hearing stories from women who said, 'I never drank during pregnancy, but now I have an FAS kid – and my male partner was a chronic alcohol abuser'," he says. But such stories often were dismissed as mothers being forgetful, if not outright lying.
Recent research, however, raises an intriguing – and possibly game-changing – possibility: these mothers were right all along.
The idea that a father's alcohol consumption before conception could have an impact on the offspring may seem far-fetched. But recent population studies have found that babies whose fathers drank are at a higher risk for various poor health outcomes. One 2021 observational study of more than half a million couples in China, for example, found that the risk of birth defects – including cleft palate, congenital heart disease, and digestive tract anomalies – was higher if the father drank before conception, even when the mother did not drink. Another population study from China compared 5,000 children with congenital heart defects to 5,000 without. Again, while overall risk remained relatively low, it found that babies were nearly three times more likely to have a congenital heart defect if their father drank – defined as having more than 50ml (1.7fl oz) of alcohol per day in the three months before pregnancy – than if he didn't.
It's important to note that the overall risk of birth defects still remained relatively low. In the 2021 study of various birth defects in China, for example, the most-impacted type – cleft palate – was found in just 105 babies of the 164,151 whose fathers drank. But this made cleft palate 1.5 times more likely among offspring of fathers who drank, than if the fathers didn't drink. "Our finding suggests that future fathers should be encouraged to modify their alcohol intake before conceiving to reduce foetal risk, considering a paternal drinking rate of 31.0% substantially elevated the risk of birth defects," the researchers wrote.
In July 2024, meanwhile, a study found that if fathers drank alcohol before conception, foetal growth appeared to be impacted.