Social changes throughout history have greatly influenced the development and emergence of new forms of family. Through this paper, we follow various aspects of adult adoption institute in Japan, Canada and the United States of America. Although it creates a parent-child relationship, its legal effects vary from society to society. Thus, this paper explains the special form of adult adoption and its impact on the preservation of traditional and economic values of individual societies. As a leading example of a country where it is allowed to adopt an adult person, we can cite Japan, where it had first been recorded in the Middle Ages. In the United States, it is permitted in certain parts of the country, but is less common than the adoption of a minor, whereas in Canadian practice it is essential that the reason for adoption is acceptable to the court regardless of the age of adoptee. Although some authors consider adult adoption as unusual practice that does not deserve deeper study, by comparing different legislations and historical circumstances of other countries we can get a better insight into our own legislative framework and better understand the circumstances and ways in which certain institutes are regulated.