“The life course is the progression and path that an individual follows from conception to death, and considers that the entire life of the individual presents opportunities for development, change and growth” (Crawford and Walker 2010). Being aware of a person's life course and the impact of transitions during their life course is important to social work practice. It is important for social workers to reflect on their own and others' experiences throughout their lives and support this understanding within different theoretical frameworks. This helps us understand common themes that have affected people throughout the ages and helps us understand why people behave the way they do in certain situations. “Understanding the life course aims to encourage us in the flexibility of imagination necessary to enter into the lives of people at different ages and see the world from their point of view” (Sudbery, 2010, p.231). This essay will critically explore why social workers need to know about the life course. To do this, it will examine the particular area of ​​sexuality and, as a related issue, adolescent mental health, one of the main risk factors related to coming out. It therefore follows that, as social workers care for service users from birth to death, it is crucial to understand what life journey one is on and the impact that moving from transition to another can have on an individual (Thomson, 2008). This will enable social workers to understand what this stage means to a service user when interpreted within their own narrative and how to support them effectively. Additionally, social workers would respond differently when caring for, for example, a teenager and a middle-aged adult. L...... middle of article...... & Human Sexuality, Volume 8, Number 1, 75 -95Mercer, LR and Berger, RM (1989). Social service needs of lesbian and gay adolescents. Adolescent sexuality: new challenges for social workers. Haworth Press. Moses, EA and Hawkins, RO (1982). Counseling Lesbian Women and Gay Men: A Problem-Focused Approach to Life. St. Louis: Mosby. Moore, S and Rosenthal, D. (1993). Sexuality in adolescence. London: RoutledgeMuss, R.E. (1966). “Theories of adolescence”. New York: Random House. American Council of Economic Advisers (2000). Adolescents and their parents in the 21st century: An examination of trends in adolescent behavior and the role of parental involvement. Washington, DC: White House Walker, S. (2008). Social work and mental health of children and adolescents. Dorset: Russell House Publishing Ltd. Thompson, N. (2009.) Understanding Social Work. Third edition: Palgrave Macmillan