This essay aims at analysing the building of social interaction a relevant dimension in the description and conceptualisation of child well being by using Sen’s capability approach. In this paper we deal with a special dimension of this capability that involves the capability of interaction between father and child, we try to define its elements with reference to Italy by using ISTAT (Italian National Statistical Office) multipurpose survey on family and on children condition in Italy (year 1998) and by implementing on these data a fuzzy expert system. The outcome is then analysed with reference to the observed characteristics of fathers and area where the family lives.