<p>A significant body of research suggests that orphans have an early onset of sexual activity and higher fertility rates compared to non-orphaned peers. However, the factors driving this disadvantage and the specific population groups affected are poorly understood. This study investigates how being an orphan and living with surviving parent(s) impacts adolescents’ sexual behavior, particularly in Africa and Asia, where many children live apart from their parents due to death or migration, along with insufficient education about sexual health. Data on the living arrangements and sexual behavior of female adolescents were obtained from Demographic and Health Surveys conducted in ten African countries and four Asian countries between 2019 and 2022. Adjusted ordinal and binary logistic models were utilized to assess the risk of structural disadvantages affecting teenage pregnancy and motherhood, while a Weibull accelerated failure model was used to examine the hazard risk associated with the timing of sexual debut. The findings from multivariate analyses indicated that females not co-residing with biological parents faced wealth-inequality-related disparities as well as educational inequalities, which were associated with a greater likelihood of initiating sexual activity earlier. When considering pooled data, it was found that teenage girls without the presence of a mother exhibited a heightened risk for pregnancy or motherhood regardless of whether the mother had passed away or was living elsewhere. Interventions aimed at delaying young girls’ initiation into sex should focus on promoting co-residence within family structures and improving access to education.</p>