Can you show us this from the Catechism, Canon Law, or some other Vatican document? I have never heard that it is completely forbidden, so I would like to see an official Church teaching on this. Thanks.
Catechism of the Catholic Church:
1150 Signs of the covenant. The Chosen People received from God distinctive signs and symbols that marked its liturgical life. These are no longer solely celebrations of cosmic cycles and social gestures, but signs of the covenant, symbols of God’s mighty deeds for his people. Among these liturgical signs from the Old Covenant are circumcision, anointing and consecration of kings and priests, laying on of hands, sacrifices, and above all the Passover. The Church sees in these signs a prefiguring of the sacraments of the New Covenant.
699 The hand. Jesus heals the sick and blesses little children by laying hands on them. In his name the apostles will do the same. Even more pointedly, it is by the Apostles’ imposition of hands that the Holy Spirit is given. The Letter to the Hebrews lists the imposition of hands among the “fundamental elements” of its teaching. The Church has kept this sign of the all-powerful outpouring of the Holy Spirit in its sacramental epicleses.
1288 “From that time on the apostles, in fulfillment of Christ’s will, imparted to the newly baptized by the laying on of hands the gift of the Spirit that completes the grace of Baptism. For this reason in the Letter to the Hebrews the doctrine concerning Baptism and the laying on of hands is listed among the first elements of Christian instruction. The imposition of hands is rightly recognized by the Catholic tradition as the origin of the sacrament of Confirmation, which in a certain way perpetuates the grace of Pentecost in the Church.”
1538 Integration into one of these bodies in the Church was accomplished by a rite called ordinatio, a religious and liturgical act which was a consecration, a blessing or a sacrament. Today the word “ordination” is reserved for the sacramental act which integrates a man into the order of bishops, presbyters, or deacons, and goes beyond a simple election, designation, delegation, or institution by the community, for it confers a gift of the Holy Spirit that permits the exercise of a “sacred power” (sacra potestas) which can come only from Christ himself through his Church. Ordination is also called consecratio, for it is a setting apart and an investiture by Christ himself for his Church. The laying on of hands by the bishop, with the consecratory prayer, constitutes the visible sign of this ordination.
1573 The essential rite of the sacrament of Holy Orders for all three degrees consists in the bishop’s imposition of hands on the head of the ordinand and in the bishop’s specific consecratory prayer asking God for the outpouring of the Holy Spirit and his gifts proper to the ministry to which the candidate is being ordained.
Pope Benedict XVI, 1-10-07:
“The act of the laying on of hands can have various meanings. In the Old Testament, this gesture meant above all the transmission of an important office, just as Moses laid his hands on Joshua (cf. Nm 27: 18-23), thereby designating his successor. Along the same lines, the Church of Antioch would also use this gesture in sending out Paul and Barnabas on their mission to the peoples of the world (cf. Acts 13: 3).
The two Pauline Letters addressed to Timothy (cf. I Tm 4: 14; II Tm 1: 6) refer to a similar imposition of hands on Timothy, to confer upon him an official responsibility. From what we read in the First Letter to Timothy, we can deduce that this was an important action to be carried out after discernment: “Do not be hasty in the laying on of hands, nor participate in another man’s sins” (5: 22).
Thus, we see that the act of the laying on of hands developed along the lines of a sacramental sign. In the case of Stephen and his companions, it was certainly an official conferral of an office by the Apostles, but at the same time an entreaty for the grace to carry it out.”
I couldn’t translate this, but it talks about the Sacrament of Holy Orders, including laying on of hands:
vatican.va/archive/catechism_lt/p2s2c3a6_lt.htm