In-depth interviews of 36 Saudi families whose children suffered from neuro-metabolic disorders were conducted at a specialist hospital in Riyadh in order to examine parental understanding of disease and attitudes towards future births and consanguineous marriages. Parents had difficulty accepting a genetic explanation for diseases that did not affect all children at the time of birth; they also expressed religious or folk beliefs to account for illness. Coping behaviours included denial and resignation to the situation, divorce and remarriage. Some families adopted a cautious approach to cousin marriages and future births; this was significantly related to their education level, but not to previous infant deaths. Awareness of medical facts brought little emotional comfort to parents but allowed for preventive measures through screening adult carriers and identifying affected infants. This study presents new material from Saudi Arabia to strengthen current awareness that the range of religious beliefs, social attitudes and reproductive behaviours adopted by families in a society undergoing rapid change is of direct relevance to health care.