If by “birth control” the priest meant artificial contraception, then he was incorrect. Artificial contraception is morally unacceptable. The Catechism of the Catholic Church (CCC) explains, “every action which, whether in anticipation of the conjugal act, or in its accomplishment, or in the development of its natural consequences, proposes, whether as an end or as a means, to render procreation impossible is intrinsically evil” (CCC 2370).
Regulation of births (through moral means), on the hand, may be a necessary aspect of responsible parenthood. “For just reasons, spouses may wish to space the births of their children. It is their duty to make certain that their desire is not motivated by selfishness but is in conformity with the generosity appropriate to responsible parenthood. Moreover, they should conform their behavior to the objective criteria of morality: When it is a question of harmonizing married love with the responsible transmission of life, the morality of the behavior does not depend on sincere intention and evaluation of motives alone; but it must be determined by objective criteria, criteria drawn from the nature of the person and his acts, criteria that respect the total meaning of mutual self-giving and human procreation in the context of true love; this is possible only if the virtue of married chastity is practiced with sincerity of heart” (CCC 2368).
Why is contraception wrong?
What is the moral difference between contraception by artificial means and NFP?
What are acceptable reasons for avoiding pregnancy?