Making decisions about when to have children and the number of children to have in marriage is seen as a sacred responsibility that God has entrusted to husband and wife. This is the foundation of what the Church calls 'Responsible Parenthood'—the call to discern God's will for one's marriage while respecting God's plan for life and love. The Catholic Church supports the methods of Natural Family Planning (NFP) because they respect God's intention for married love by remaining open to the procreative possibility of sexual intercourse, whilst at the same time using human knowledge of the fertile periods to regulate births.