Catechism of the Catholic Church
c. Para. 1252: The practice of infant Baptism is an immemorial tradition of the Church. There is explicit testimony to this practice from the second century on, and it is quite possible that, from the beginning of the apostolic preaching, when whole "households" received baptism, infants may also have been baptized (Cf. Acts 16:15, 33; 18:8; 1 Cor 1:16; CDF, instruction, Pastoralis actio: AAS 72 [1980] 1137-1156).
Para. 1282: Since the earliest times, Baptism has been adminstered to children, for it is a grace and a gift of God that does not presuppose any human merit; children are baptized in the faith of the Church. Entry into Christian life gives access to true freedom.
Para. 1250: Born with a fallen human nature and tainted by original sin, children also have need of the new birth in Baptism to be freed from the power of darkness and brought into the realm of the freedom of the children of God, to which all men are called (Cf. Council of Trent [1546]: DS 1514; cf. Col 1:12-14). The sheer gratuitousness of the grace of salvation is particularly manifest in infant Baptism. The Church and the parents would deny a child the priceless grace of becoming a child of God were they not to confer Baptism shortly after birth (Cf. CIC, can. 867; CCEO, cann. 681; 686, 1).
Para. 1251: Christian parents will recognize that this practice also accords with their role as nurturers of the life that God has entrusted to them (Cf. LG 11; 41; GS 48; CIC, can. 868).