Birth order plays an essential role in different cultures from all over the world. It goes without saying that the birth order plays significant role in the process of the development of the self-concept, which means that it has also a lot to do with the further social status. As a child who is neglected and criticized at home may develop a negative self-concept, and the same with other approaches from the family. Different positions of birth order create certain differences between siblings. Through our life cycle we play different roles. These are ascribed roles and achieved ones. As we do not have any control over our ascribed roles, we form our individuality through our achievements, that is to say achieved roles. Through earning our individual accomplishments, we come across to the widely spread word-combination “sibling rivalry”. The birth order does not just separate siblings by the years of birth, but also effect on their self-concept, behavior, reactions, future social status and life-style. Alfred Adler was the first to speak about the meaning of the birth order for the future life of a child and the differences between the children in accordance with their birth order. According to the research of Alfred Adler, who was also the founder of individual psychology and the second child in his family, the birth order of a child is the predictor of his future characteristics and peculiarities. Adler believed that the true reason for such differences between siblings is