A large number of couples who end up their reproductive career with only one child presents a serious problem for demographic trends of a region in which they reside. A question rarely posed is what kind of consequences that phenomenon has for a family climate and family dynamics of those families. An even more important question is what kind of consequences the same phenomenon has for personality development of a child who grows up as a single child. What kind of characteristics and what personality traits are more likely to develop in a child that grows without his/her siblings? The results of our research show that single children get better results on the tasks that require recognition of one’s own emotional states and motives of one’s own behavior than first born and second born children. However, single children score less favorably than first or second born on the tasks that require forecasting other people’s behavior. The explanation for this may be that single children are self-centered due to the lack of interaction with siblings. Other possible explanation may be a specific parenting style that a single child receives from his/her parents. This parenting style is uniquely different from parenting style that a second or third born child receives due to the unique situation created by the fact that he/she is a single child.