Introduction
According to many experts, the issue of generation gap was not an issue worthy of attention until the emergence of the industrial society, and even before the 20th century, it was not an obvious issue, it was not considered a social issue. But in this century, with the growth and expansion of information and communication technologies and the speed of social and cultural changes, the conflict and gaps between generations are increasing day by day, so that most social scientists mention the phenomenon of generation gap. Generational gap is a concept that shows significant psychological, social, and cultural differences and significant differences in vision, awareness, beliefs and imaginations, expectations and value orientations and behavioral patterns between two generations at the same time in a society. Generation gap is a phenomenon that can have deep effects on family functions, social cohesion and sustainable development of societies. For example, in the current situation, the relationship between parents and children has turned cold, and two generations, due to social differences and different experiences, look at life from their own point of view and interpret it according to their own vision. Yesterday's generation (parents' generation)feel knowledgeable and experienced, and today's generation (children and teenagers) who want to adapt to today's developments, react because they cannot cope with their logic and advice rooted and full of experience, they turnto gambling. Therefore, the present study aims to identify and discover the factors affecting the generation gap based on the lived experience of teenagers and their parents in Tehran using the grounded theory method and designing a paradigm model in this field.
Research question and hypothesis
According to the said contents, the question that the present research aims to answer is that, based on the lived experience of the participants, that is, parents and children, what are the most important causal, contextual and intervening factors and conditions affecting the gap between the two generations, and what are the strategies resulting from these conditions and the consequences of these factors?.
Theoretical framework
French sociologist Bourdieu, who is influenced by the macro-Marxist perspective and conflict approach, does not consider intergenerational challenges as other social conflicts, independent of class and stratification system or systems of dominance and inequality in different fields and within the framework of inequality and social conflict. It analyzes generational relationships and conflicts. Inglehart believes that rising levels of economic development, higher levels of education, the spread of mass media, and the rise of the welfare state lead to changes in the most important values. Berger (1929) and Luckman (1927) have explained the phenomenon of generation gap in the form of unsuccessful social education and believe that today due to the multitude of socializing institutions, value unity is lost and value plurality replaces it


Materials & Method
The method of conducting the current research is a qualitative type of grounded theory. Due to the importance of the issue of the generation gap and the need to understand it more and better, and the lack of insight and sociological knowledge in relation to it, the qualitative, inductive and exploratory method of the grounded theory was selected. In the first step, in order to collect data related to the problem, adolescents aged 15 to 19 years and their parents have been considered as the statistical population of the research to express their opinions from different perspectives. For this purpose, using targeted and accessible sampling method, ­40 boys and girls and their parents were selected as participants and the statistical community and they were interviewed. The purpose of conducting the interviews was to collect the necessary data about the factors affecting the generation gap by the theoretical sampling method (focusing on the data) to the extent that it is sufficient and desirable. According to the theoretical model of the approach, a category was selected as a "central category" and around it, conditions and causal, contextual and intervening factors were identified, and finally, based on these factors, strategies and consequences were determined and the research model was designed



Discussion & Results
The current research aims to investigate and discover the factors affecting the generation gap among teenagers and parents in Tehran based on the life experience of both generations using the grounded theory method. Based on the definition, intergenerational gap and challenges refer to differences, conflicts and differences in values, behaviors and attitudes between two generations, which can ultimately lead to their distancing from each other.
Thus, in this research, according to the grounded theory method and with continuous comparison of data and interviews, "disagreement, conflict and challenges between parents and teenagers" was chosen as the central phenomenon of the research because it was the topic and focus of all the interviews and all the events, concepts, subcategories and main categories of the research were aimed at analyzing and explaining its occurrence in the society, and the course of the discussion showed the formation of a basic theory around it. Among the most important primary and preliminary factors that lead to the gap between the two generations, we can mention the atmosphere of mistrust and the existence of negative ideas between the two generations, the pluralism and change in the lifestyle of the new generation, the commodification of the relations between the two generations, and the linguistic division. Background conditions that can create a special background and cause the occurrence of "parent-child conflict" can be mentioned as ignoring the wishes, desires, and wishes of the children by the parents, the eyes and eyes of the parents towards each other and comparing their children with other friends and acquaintances. Meanwhile, the strategy used between the two generations is also different; This means that parents resist their children, do not adapt themselves to the age of technology, and resist new conditions and styles (parents' stubborn resistance strategy). On the other hand, the children have turned to play tricks against this resistance and adapt themselves to the new conditions, cultural and social changes (the strategy of adapting to the new conditions and lifestyle).


Conclusion
If there are no facilitating and mediating institutions in this field, this gap and contradictions between parents and children can lead to a break in emotions and feelings, the loss of sanctity and sanctity of the family, the formation of shadow and parallel institutions, and a decrease in the economic growth and productivity of the society. Therefore, it is suggested that each of the generations adjust and adjust their values, norms, standards and lifestyle as much as possible, interact and dialogue with each other and in this way strengthen the foundations of the family and build a homogenous family based on dialogue and democracy.