Research into child development began at the end of the 19th and the beginning of the 20th century, and due to great interest, various theories appeared that provide different ideas about what children are like and how they change. The authors agree that children are complex beings that change physically, cognitively, emotionally and socially (Berk, 2015). Genetic inheritance is the basis of development, and the environment in which development takes place is very complex because it consists of a multi-layered set of influences that combine with each other to have a favorable or unfavorable effect on physical and psychological health. The importance of the family is extremely great because the family is the first and longest-lasting context of development (Berk, 2008). Within the family, unique bonds develop between people such as attachment to parents and siblings, which regularly lasts a lifetime and serves as a model for creating relationships in the wider world such as the neighborhood, school and community. Emotionally warm and supportive family ties are predictive of physical and psychological health throughout life. In contrast, isolation or estrangement from family is often associated with developmental problems (Parke and Buriel, 1998; according to Berk, 2008). It is important that parents talk to their children, answer their questions and encourage them to explore in a safe environment (Berk, 2008). The ability to regulate emotions develops in early childhood from interaction with family members and from the child's natural temperament, and children's social development includes behaviors, attitudes and affects united in the child's interaction with other adults and peers (Brajša-Žganec, 2003). In his theory of ecological systems, Bronfenbrener points out that the environment outside the microsystem strongly influences development. Culture affects all aspects of everyday life, interactions in the family and extrafamily environments present in the community (Berk, 2008).