The study examines the occurrence of children born out of wedlock in four parishes belonging to the current Karlskrona municipality during the period 1875–1925. The parishes surveyed are Fridlevstad, Rödeby, Tving and Karlskrona city-parish. The period is divided into two parts where the first includes the years 1875–1890 and the second part includes the years 1910–1925. The proportion of children with unknown/known fathers, the mothers' occupations, the fathers' occupations, and the mothers' age are also used as survey variables.

The proportion of known fathers increases significantly between the study periods, which could be explained by a reduced internal social control, while the study shows that the introduction of a child welfare officer in 1918 resulted in an increased proportion of known fathers.

The mothers' occupational designations change between the periods, for example, the proportion of maids decreases while other occupations are added. In the city-parish, professions such as washerwoman and waitress are added during the second period. The proportion of women working in the industry also increases between the survey periods. The increased proportion of professions, especially in the city-parish, could be linked to the demographic transition. As more people settle in a city, new needs emerge and thus also new occupational categories. The age of the mothers decreases between the study periods.

When it comes to class affiliation, it can be noted that most of the fathers and mothers belonged to the working class. However, the proportion of fathers belonging to the middle class was higher than the proportion of mothers belonging to the middle class.