The real and rather interesting non-religious argument against contraception:
Oddly enough, Pope Paul VI, author of Populorum Progresso predicted exactly this in Humanae Vitae.
Going back to Papal Economics, Fr. Zieba claims that Pope Paul VI was disconnected from reality on economics in his encyclicals. I put forth that he was in fact *very* attached to the reality of the law of supply and demand- and could see coming that human beings were losing out to the impersonal equation dictating price- is exactly why Populum Progresso looked to the State for some sort of balance in enforcement of morality, and in Humanae Vitae, called for an end to contraception to reset the high price of sex.