While many earlier studies have shown a positive correlation between parents' education and children health, little attempt has been made to address the possibility that unobserved characteristics underlie this intergenerational relationship. This paper explores the effect of additional schooling induced through compulsory schooling laws in Great Britain and Northern Ireland on child health as measured by long-term illness. Despite statistically significant ordinary least squares estimates, the instrumental variable estimates reveal little if any causal relationship between parental education and long-term illness in children. This is true for both two-parent and single-parent families.