The transition to parenthood is critical in producing and amplifying gender inequalities in work and family life. After parenthood, mothers take on the vast majority of childcare responsibilities, which slows down their income development and career opportunities to a much greater extent than for men. This project reveals sources of gender inequality in work and care after parenthood by studying income trajectories and parental leave use across different family types: male and female same-sex couples, adoptive and biological different-sex couples, and multiparent families. By comparing these family types, we unravel how skewed divisions of labor are explained by (1) pregnancy/giving birth, (2) biological ties, (3) norms towards mothers as caregivers and fathers as breadwinners, and/or (4) motherhood/fatherhood identities. We use longitudinal register data from Denmark, Finland, Sweden and Norway to create the largest, representative cross-national dataset on each family type to date, allowing us to be the first to quantitatively asses work and family patterns of gay fathers and multiparent families. Studying work and family life in diverse families allows us to (i) develop sociological thinking by testing established theories on gender, work and care on new families, (ii) generate knowledge on how to reduce remaining inequalities in the home and labor market, and (iii) aid government programs and policies to more accurately reflect the diversity of families in their society.