Family structure and social disadvantage are thought to have adverse effects on the outcome of diabetes mellitus (DM). While there are data on family functioning and maternal coping in relation to some measures of metabolic control, little is known about the role of fathers in respect to coping and outcome of DM. We are presently conducting prospective studies to assess the role of fathers in families with children with DM. In addition, family functioning and psychosocial factors are being investigated in relation to putative effects on metabolic control. Structured questionnaire studies are being performed in 182 children and adolescents with type 1 DM. Similar questions are also put to the families. Mean age of the patients is 12.9 years, range 1.8-18 years, with an equal distribution between the sexes. Metabolic control as assessed by the mean of the last four HbA1c values (HPLC method; intra-assay coefficient of variation [CV] 2.1-3.3%, interassay CV 2.6-4.3%) is 7.4%; range 5.0-14.8%. The patients attend outpatient clinics at an average interval of six weeks. Structured educational in-patient programs are attended by less than one-third of the patients. There is a large prevalence of unemployment in the families. In the majority of cases mothers accompany their children to the clinic while fathers are absent. It is the mothers who adjust daily insulin doses, take care of food preparation and ensure the children's self-assessment. In conclusion, our preliminary data suggest that the role of fathers in diabetes management is rather passive and emotionally labile. Special educational programs targeted towards the fathers of children with DM and towards improving parental interactive strategies are urgently needed to better use parental resources of coping and support.