Paternity is the legal link between the father and the child and results from the fact that a man has conceived the child. Paternity may be either from marriage or from outside marriage. The filiation toward the father in marriage is determined by the effect of the presumption of paternity according to the law, and the paternity filiation toward the father outside the marriage is established, either by the recognition of the father or by the court. In the case of medically assisted human reproduction with a third-party donor, the filiation toward the father shall be based on the consent of the mother’s spouse or concubine to be considered the child’s father. In the case of the child in marriage, the presumption of paternity is the only way of establishing the filiation toward the father and operates ope legis. If the mother’s husband is impossible to be the father of the child, the paternity can be negated, but only by court.