 He was appointed as Professor of Sociology in 1971.He took an interest in family research already in the 1950s, and has published several books on family, gender roles, work, sexuality and society.In cooperation with developmental psychologist Per Olav Tiller he conducted a seminal study on father absence in sailor families and its impact on children's personality development during the 1950s and 1960s; the study was the first study on men in the Nordic countries.