'When I was pregnant with my son I drank a lot – mostly on weekends,' says Marion Williams, a 45-year-old mother who lost two of her five children in childbirth. Williams lives in one of South Africa’s famous wine-growing areas in the Western Cape. She started drinking as a teenager and was taken out of school, she suspects, to work to buy wine for her parents. 'It is estimated that at least one million people in this country have fetal alcohol syndrome and approximately five million have partial fetal alcohol syndrome and [other] fetal alcohol spectrum disorders. It’s tragic because it’s completely preventable,' says researcher and human geneticist Denis Viljoen in Cape Town, the provincial capital of South Africa’s Western Cape.