From the Compendium of the Catechism:
- When is it moral to regulate births?
2368-2369
2399
The regulation of births, which is an aspect of responsible fatherhood and motherhood, is objectively morally acceptable when it is pursued by the spouses without external pressure; when it is practiced not out of selfishness but for
serious reasons; and with methods that conform to the objective criteria of morality, that is, periodic continence and use of the infertile periods.
- What are immoral means of birth control?
2370-2372
Every action - for example, direct sterilization or contraception - is intrinsically immoral which (either in anticipation of the conjugal act, in its accomplishment or in the development of its natural consequences) proposes, as an end or as a means, to hinder procreation.
- Why are artificial insemination and artificial fertilization immoral?
2373-2377
They are immoral because they dissociate procreation from the act with which the spouses give themselves to each other and so introduce the domination of technology over the origin and destiny of the human person. Furthermore, heterologous insemination and fertilization with the use of techniques that involve a person other than the married couple infringe upon the right of a child to be born of a father and mother known to him, bound to each other by marriage and having the exclusive right to become parents only through each another.
- How should children be considered?
2378
A child is a gift of God, the supreme gift of marriage. There is no such thing as a right to have children (e.g. “a child at any cost”). But a child does have the right to be the fruit of the conjugal act of its parents as well as the right to be respected as a person from the moment of conception.