In the Netherlands, if a man and a woman are not married or are not in a registered partnership, then the man will not automatically be recognised as the lawful father of any children that they may have. This is irrespective of the fact that the man is the child’s biological father.
If you are not married and your partner wants to be regarded as the child’s lawful father, he must go through the formal process of acknowledging that he is the child’s rightful father. This also applies if you are in a cohabitation agreement. Complying with the Dutch process of formally acknowledging the child may be important for giving the right of inheritance, nationality, determining parental access and/or parental guidance.
Further information on the subject can be found at the following Dutch government website: www.government.nl/issues/family-law.
In a marriage or registered partnership between two women, the biological mother is automatically registered as parent. How the co-mother can become registered as a legal parent, either automatically or by acknowledgement, is explained on the Dutch government’s website.