How is NFP different from the sin of Onan?
The short answer
Onan's sin was deliberately making the marital act sterile. NFP never makes any act sterile — every act stays open to the possibility of new life. It simply regulates pregnancy by abstaining during the woman's fertile time.
What Onan did
Onan spilled his seed on the ground in order to make the act sterile.
Not the "waste" of seed
His sin was not that seed was wasted. In ordinary marital relations, seed often does not result in pregnancy. The sin lay in acting so as to sterilize the act on purpose.
Why NFP is different
Natural family planning never tries to make an act sterile; every act remains open to procreation. NFP regulates pregnancy by observing abstinence during the woman's fertile period.
Continue exploring
- Does the Church allow birth control in certain circumstances?Q&A
- Are marital relations not supposed to be pleasurable, since they are for reproduction?Q&A
- May we use birth control to avoid a difficult pregnancy?Q&A
- Did Fulton Sheen take a permissive stand on contraception?Q&A
- If sex is good for us, why is the Church so hostile to it?Q&A
- Is marital intercourse sinful if the spouses do it with lust for each other?Q&A