No, I don't know of any official document from the Holy See about this, but we have simply applied common sense and logic. As human beings, we must be persons, not artificial constructs, in order to transmit faith. The Sacraments can only be administered by a validly ordained priest, physically and not artificially. So, I think this issue is not about saying, 'We have to,' or 'We must not use this in the transmission of faith.' It must be done personally, as a person, with conscience. This upholds the dignity of human beings and Christians, as the Lord also came to us personally, incarnated, and spoke to us. We should not have an artificial father or mother, nor should we have an artificial husband. We must be personal and concrete, and God is concrete. To avoid this, we must be cautious of Gnosticism and the artificial world. We must stress the reality that God incarnated in this real world.