Infant baptism - Wikipedia

Infant baptism or pedobaptism, the baptism of the infant children of believers, is an ancient custom of much of Christianity, including the Roman Catholic church, the Orthodox churches, Anglicans, Lutherans, Presbyterians, and Methodists, to name a few. Churches with the name "Baptist" in their titles usually practice Believers baptism.

Since baptism is the rite of initiation into the church, pedobaptists recognize that the children of believers become are both members of their nuclear families and members of the church to which their parents belong. The alternative would be to treat them as mere unbelievers or inquirers. Pedobaptism also recognizes that membership in the church is not just a matter of intellectual understanding and assent. It is thus much easier for churches that practice pedobaptism to include people who are mentally impaired and may never be capable of intellectually understanding the creed, but nevertheless practice their faith and participate in the church as they are able.

Opponents of pedobaptism claim that is unbiblical. Pedobaptists however point to a number of passages where reference is made to baptising a person and their household – the households of Lydia, Crispus, and Stephanas are mentioned by name Acts 16:14-15, 18:8; 1 Cor 1:16 (http://bible.gospelcom.net/bible?acts+16:14-15;18:8;1cor+1:16). Pedobaptists argue that one's household would include ones children, even infants, and add that this is how the Church has traditionally understood baptism throughout its history.