Paternity is the relationship established by law between the father and his child. In Thailand, paternity is presumed inside a valid marriage and any child born in a valid Thai marriage is considered as legitimate child of the husband. Paternity in Thailand can only be established by marriage, court decision and government registration, aside from these methods the man will not be considered as the child’s father.
By default, a child born outside of a marriage is an illegitimate child and only the mother can claim legal rights over the child. Even if the father acknowledges the child as his, the father’s rights over the child does not apply automatically. If the biological father wishes to establish a legal relationship with the child, he should be married to the mother, or register the child as his own, or file a court action for that purpose. Marriage between the mother and biological father of the child does not automatically make the child legitimate, and only marriages recognised by Thai law can make the child legitimate.
Legitimacy is presumed for children born as a result of a valid marriage, while divorce on the other hand complicates some legality. When a child is born prior to the finality of a divorce, the child is still considered as legitimate. The husband would be considered as the legal father of the child whether the woman was impregnated by him or another man. If the child is born after the divorce but within the 310 days from the termination of the marriage, the child would still be considered as legitimate. This presumption is created by law and the former husband is still considered as the legitimate father of the child.
Repudiation of paternity refers to a man who believes that he is not the father of the child born by his wife or ex-wife. It is also the remedy if child support is required from a man. The putative father can request the Thai court to run a DNA test, which will be administered by the Thai authorities and paid by him. A proof of cohabitation with the child’s mother being impossible within the 310 days before the birth can also be submitted. Until non-paternity has been proven by the father either by DNA testing or proof of non-cohabitation with the child’s mother, the child would still be considered as his. Only the Thai court can rule the repudiation.