In Pope Paul VI's Humanae Vitae, paragraph 14 titled, Unlawful Birth Control Methods states, "...We are obliged once more to declare that the direct interruption of the generative process already begun and, above all, all direct abortion, even for therapeutic reasons, are to be absolutely excluded as lawful means of regulating the number of children. (14) Equally to be condemned, as the magisterium of the Church has affirmed on many occasions, is direct sterilization, whether of the man or of the woman, whether permanent or temporary. (15)" He said that no artificial method and under no circumstances is birth control allowed. He believed that marriage and sexual intercourse are for procreation purposes only, and whatever uses and methods of contraception that are used are strictly prohibited and looked down upon by the Church. If any type of birth control was used, it was considered a sin because it is interfering with the way of God's plan.
While Pope Paul VI believed in a 'fixed and unchanging human nature,' history goes to show that human nature is forever changing and will continue to change, shaping and reshaping itself. In modern day, not everyone believes in the Catholic Church; some people don't believe in religion at all. Obviously, there are lots of people in the world who don't believe in the idea of "God's ultimate plan for human life." These individuals don't deserve to be ridiculed, frowned upon, and to be called sinners by the Catholic Church. It's just not fair that the so-called "non-believers" turn into sinners. Just because Catholicism was one of the first religions, doesn't mean that everyone should follow in its teachings and beliefs. Freedom of religion is a right that everyone has (in America, anyway) and everyone should be treated equally regardless of his or her religious beliefs.
The Pope socially constructed this to be something evil and since he is so influential to many, it is hard to socially reconstruct the idea of birth control. To prove that human nature is ever changing, now, birth control has gained a lot of popularity and lots of people are engaging in safer sex. Back in the late 1800s- early 1900s, families would have many children and some would die because the parents did not have enough resources to provide them with a healthy life. This, in my opinion, is worse than using contraceptives to prevent having these kids in the first place. Being a responsible parent is knowing whether or not you have the resources to provide for your future children, if not then you shouldn't be having kids at all. But under Catholic "law", any method of birth control was illegal, so if God granted you with a child, it was there to stay. Pope Paul IV also stated that marriage and sexual intercourse were for procreation purposes only. Back then, people got married for economic or social status reasons. Now, marriage is (or should be) about love. Sexual intercourse isn't necessarily only for baby making, it should be a way of expressing that love. Marriage shouldn't and isn't all about having kids either. There are plenty of people who get married and don't want kids.
History and culture are socially constructed by the people that live in that time. It is ever changing and will continue to change without a doubt. The norm and all things deemed "ok" by society now are very different than the norm more than a century ago, in Pope Paul VI's time.