Since the form of baptism requires just the water and the words, the sacrament, like the Sacrament of Marriage, does not require a priest; any baptized person can baptize another.

In fact, when the life of a person is in danger, even a non-baptized person—including someone who does not himself believe in Christ—can baptize, provided that the person performing the baptism follows the form of baptism and intends, by the baptism, to do what the Church does—in other words, to bring the person being baptized into the fullness of the Church.

In certain cases where a baptism has been performed by an extraordinary minister—that is, someone other than a priest, the ordinary minister of the sacrament—a priest may later perform a conditional baptism.

A conditional baptism, however, would only be performed if there were grave doubt about the validity of the original application of the sacrament—for instance, if a non Trinitarian formula were used, or if the baptism had been performed by a non-baptized person who later admitted that he did not have the proper intention.

A conditional baptism is not a "rebaptism"; the sacrament can only be received once.

And a conditional baptism cannot be performed for any reason other than grave doubt about the validity of the original application—for instance, if a valid baptism has been performed, a priest cannot perform a conditional baptism so that family and friends can be present. 

 Infant Baptism

In the Catholic Church today, baptism is most commonly administered to infants.

While some other Christians strenuously object to infant baptism, believing that baptism requires assent on the part of the person being baptized, the Eastern Orthodox, Anglicans, Lutherans, and other mainline Protestants also practice infant baptism, and there is evidence that it was practiced from the earliest days of the Church.

Since baptism removes both the guilt and the punishment due to Original Sin, delaying baptism until a child can understand the sacrament may put the child's salvation in danger, should he die unbaptized.

 Adult Baptism

Adult converts to Catholicism also receive the sacrament, unless they have already received a Christian baptism. (If there is any doubt about whether an adult has already been baptized, the priest will perform a conditional baptism.)

A person can only be baptized once as a Christian—if, say, he was baptized as a Lutheran, he cannot be rebaptized when he converts to Catholicism.

While an adult can be baptized after proper instruction in the Faith, adult baptism normally occurs today as part of the Rite of Christian Initiation for Adults (RCIA) and is immediately followed by Confirmation and Communion.

The Effects of the Sacrament of Baptism

Baptism has six primary effects, which are all supernatural graces:

1.   The removal of the guilt of both Original Sin (the sin imparted to all mankind by the Fall of Adam and Eve in the Garden of Eden) and personal sin (the sins that we have committed ourselves).

2.   The remission of all punishment that we owe because of sin, both temporal (in this world and in Purgatory) and eternal (the punishment that we would suffer in hell).