After the end of World War I, in 1918, Poland regained its independence to once again find its place on the map of the world after 123 years. Thus, Polish jurists were faced with the task of creating an entirely new legal order, in the realm of the law of the state system as well as criminal, administrative, civil, and family law. The evolution of the questions pertaining to the parentage of a child was key in the realisation of the child’s right to know their identity, in granting children citizenship of the newly founded state of Poland, and in securing their social, civil, and political rights. The laws of the previous governments would clearly stigmatise children born illegitimi thori. The year 1946 brought the first mitigation of the division into marital and non-marital children, and in 1950 the division was abolished. The subsequent legislative changes were aimed to follow the advances in biological and medical sciences. In its directives the Supreme Court wold accept the successive methods of establishing parentage moving gradually from the prevalence of personal sources in court proceedings to that of DNA tests. Exegesis of legal text and analysis of judicial decisions and literature. After one hundred years of adapting legal regulations to social changes and scientific discovery Poland still faces the necessity to regulate the crucial issues of in vitro fertilisation and surrogacy. The one-hundred-years evolution of legislation and jurisdiction in Poland in the context of the development of new methods of establishing parentage is described in the present paper.