The above is the lie, below is the truth, which even Wikipedia admits, namely, that the child grew up willingly as a Catholic, became a priest and died at the age of 88 in Belgium, just after the outbreak of WWII.

What are the Catholic principals on this matter?  Yes, Catholic servants should NOT baptize the children of their employers, regardless of their religion, unless the child is in proximity of death, and then a Baptism can be performed in secret by merely pouring water over part of the body of the child and reciting the baptismal formula, “I baptize you, (Name the child), in the Name of the Father, and of the Son, and of the Holy Spirit. Amen.”.  If the child is brought back to life or recovers, the servant should inform the Bishop. — In this case one might speculatively argue about whether the servant was a good judge of medicine, but the vocation of the child later in life proves the grace. Pius IX did the right thing, and this case is cited against him by the enemies of Jesus Christ, the only Savior of Jews and Gentiles.