Existing research documents substantial disparities in life outcomes between same-sex and different-sex attracted individuals, typically disadvantaging same-sex attracted individuals. We analyse how parental background relates to adult children’s earnings, health, fertility, and family formation by sexuality. To do so, we develop a new strategy to identify same-sex couples in population-wide administrative data using joint financial commitments from Denmark. Our approach mitigates limitations associated with non-representative surveys and cross-sectional data on sexuality. We find that disparities in outcomes persist across the parental income distribution; (dis)advantages for same-sex attracted individuals are only partially mediated by parental income. We explore parent-child dynamics as potential mechanisms, including proximity to parents. Results are robust to controlling for unobserved parental heterogeneity through sibling fixed effects, but vary across childhood regions and cohorts. Our findings suggest that intergenerational mobility depends not only on factors shared by siblings but also on innate individual characteristics, such as sexuality.