It is always a challenge to involve parents in child-development research, and there are a number of reasons why parents do not participate in such research. These include: inadequate invitations to take part, lack of time or long-term absence of the parent, the character of the study, problem behaviour occurring in the family, and parental involvement in the child´s life. In many “family studies”, it is often the case that only the mothers’ opinions are represented, and, in fact, the need to recruit fathers in research has subsequently increased in recent years, as it can present different views to those only including mothers. The aim of this study was to uncover the above differences with respect to (1) socio-demographic indicators; such as gender and the financial situation of the family, (2) health-risk behaviour (alcohol use, smoking, drunkenness) and problem behaviour, (3) parental processes (parental disclosure, solicitation, knowledge, monitoring/rules-setting) and parent-child relationships (companionship, conflict, intimate disclosure, affection, reassurance of worth, satisfaction, antagonism, punishment and relative power). This research also aims to identify what might increase the probability of parental participation in child development research.