Starting from 1 March 2002, same-sex couples have been able to register their partnerships.

Persons living in the household-dwelling unit who are not members of the nuclear family are not included in the family population, even if they are related, unless they form their own family.

The number of children refers to the number of children who are living at home and have the status of a child.

Only registered partnerships are recorded in the statistics.

A family consists of a married or cohabiting couple or persons in a registered partnership and their children living together; or either of the parents and his or her children living together; or a married or cohabiting couple and persons in a registered partnership without children.

A family can consist of no more than two successive generations.

If the household-dwelling unit comprises more than two generations, the family is formed starting from the youngest generation.

A woman with a family is a married or cohabiting partner, a mother with children and both partners of a registered female couple.

Referencing instructions: Official Statistics of Finland (OSF): Families [e-publication]. Helsinki: Statistics Finland [referred: 9.11.2017]. At the same time as parents register the name of their new-born, they also indicate the child's mother tongue.That language is retained in the Population Information System unless it is changed upon separate application.In the family statistics children comprise all persons, regardless of age, who live with their parents, or the spouse's biological or adopted children, but not foster children or children in the care of the family.Information on language is obtained from the Population Information System.Languages are classified by the Population Register Centre according to the ISO 639 standard.