Legitimate and illegitimate children.
It is important for citizenship whether a child is legitimate or illegitimate.
In the period from January 31, 1920 to January 18, 1951, the rule was that legitimate children acquired citizenship after their father, and illegitimate children after their mother. In addition, legitimate children lost their Polish citizenship together with their father, but illegitimate ones did NOT lose their Polish citizenship together with their mother.
However, illegitimate children could acquire Polish citizenship from their father by recognition, adoption or entitlement. Recognition meant that the man recognized the child as his or her own, adoption meant adoption and the entitlement meant marriage of the father of a child and the mother of an illegitimate child.
Interestingly, the law now recognizes that a person is considered a child until the age of 18, but it is the case only from January 1, 1946 (entry into force of the Personal Law). Earlier, various regulations were in force in Poland from the period of partitions. For example, according to art. 345 of the Civil Code of the Kingdom of Poland, the age of maturity reached the age of 21. The Universal Book of Civil Acts (ALLGEMEINES BÜRGERLICHES GESETZBUCH) in the Austrian Partition spoke about 24 years (§ 21). The CIVIL CODE in force in the Western Territories of the Republic of Poland (BÜRGERLICHES GESETZBUCH) established the age limit of 21 years.
In the period from January 19, 1951 to August 21, 1962, the issue of the child's origin ceased to matter. However, from August 22, 1962, a restrictive regulation was introduced, according to which extramarital children obtained Polish citizenship only on the condition that children will be recognized within one year of their birth (unless paternity is determined by court).