Having discussed the morality of various means of birth control, now it is necessary to discuss which reasons for limiting births are morally legitimate. Paul VI identifies “physical, economic, psychological and social conditions,” as in need of attention by spouses who would become responsible, prudent, and generous parents. The Compendium of Social Doctrine of the Church (CSDC) clarifies, that in weighing these issues,
The judgment concerning the interval of time between births, and that regarding the number of children, belongs to the spouses alone. This is one of their inalienable rights, to be exercised before God with due consideration of their obligations towards themselves, their children already born, the family and society (234).Spouses are not to make this decision on this issue on whims or personal preferences, but according to “objective criteria” (GS 51.3). The question of what particular quantity or frequency of births is both responsible and generous is, however, particular to circumstances and so spouses must consider this prayerfully and under the guidance of their spiritual fathers or mothers.