So where did Jesus denounce contraception?
In explaining the Church's teaching about contraception, many people mistakenly think that this teaching is relatively new, something which occurred with Humanae Vitae in 1968.
Other people, from a more fundamentalist bent, want to know if there is any basis in Sacred Scripture for these teachings. In reviewing both Sacred Scripture as well as the history of our Church's teaching in this area, one finds a very positive and solid foundation, as has been presented to date.
Concerning "What does the Bible have to say?" the very positive presentation concerning creation, marital love, and covenant emerges from the texts of Sacred Scripture. However, we also discover references to any violation of the unitive-procreative dimensions of marital love and to the divine consequences which followed. In Genesis, we find the story of Onan, the second son of Judah, who married Tamar, the widow of his older brother Er. (The Levirate law of Judaism prescribed that if the oldest brother died, the next oldest, single brother would marry his widow to preserve the family line.) The Bible reads, "Onan, however, knew that the descendants would not be counted as his; so whenever he had relations with his brother's widow, he wasted his seed on the ground, to avoid contributing offspring for his brother. What he did greatly offended the Lord, and the Lord took his life." (Cf. Genesis 38:1ff). Here is a basic form of contraception � withdrawal, and clearly a sin in the eyes of God....
http://www.catholiceducation.org/articles/religion/re0663.html