Can drinking by biological fathers cause FASD?

The importance of a father consuming alcohol before conception is an area of active research internationally. FASD is the result of direct exposure to alcohol’s toxic or ‘teratogenic’ effects on the developing cells of the foetus.

Historically it's always been the mother's 'fault' if FASD occurs, so even though many mothers have insisted they did not drink during pregnancy, it's often assumed by professionals that they have played down their alcohol use because of stigma.  Consequently, FASD prevention programs have primarily focused on women, where the evidence was certain, and treated paternal drinking as largely a risk factor for encouraging maternal drinking, rather than a risk factor for FASD itself.

However there is now some evidence that alcohol consumed before conception by the father may alter gene expression and set up a predisposing risk factor for some individuals. 

For over 30 years, there have been studies seeking to understand if paternal drinking affects fetal and infant health and may contribute to FASD in particular. However, conclusions were unclear until fairly recently, when advances in epigenetic research began to show that paternal factors, and alcohol use in particular, play a larger role in fetal/child health than just passing along genes. 

Early studies showed low levels of paternal drinking led to underdeveloped sperm resulting in conception problems and miscarriage. Others showed an increased risk of miscarriage when men drank 10 drinks or more per week in the preconception period, and one study found an association of all cases of ventricle malformation (heart defect) with daily paternal alcohol consumption during the preconception period.

A 2016 study focused on birth defects and links to paternal alcohol consumption, age and environmental factors. Deficiencies in brain size, heart formation, and cognitive and motor abilities (noted as being symptoms of FASD) were linked to paternal alcohol use even when there was no maternal alcohol consumption.

These results provide evidence to expand prevention efforts to men, especially in the preconception period, and to continue research in the field of epigenetics and alcohol-exposed pregnancy. 

It is recommended that men intending to conceive a child do not drink for 60 days before conception as an approach which carries the least risk to the unborn baby. It will also help the mother if the father is supportive in abstaining from alcohol at this important time.

Read this article (November 2023) for more information about risks to the foetus from fathers drinking alcohol.