The article is an analysis of law according to the problem of Baptism of child in the situation that only one parent gives consent and the other parent expressly disagrees. Due to the specificity of the problem, the provisions of two legal orders were analysed: canon law and Polish state law. In this way, it was possible to demonstrate the autonomy of the Catholic Church in spiritual matters, and as a consequence, the autonomy of canon law in legislating on the sacraments. Such autonomy is confirmed by the sources of state law: the Concordat between the Republic of Poland and the Holy See, and the act on relations between the State and the Catholic Church. In practice, this autonomy is respected, which can be determined on the basis of the jurisprudence of Polish courts.