Pope Francis recently beatified Pope Paul VI, who served the Catholic Church as the bishop of Rome 1963-1978. (“Beatification” is one step below being canonized a saint.)

Paul VI had a jam-packed papacy, including finishing the Second Vatican Council, traveling to all six inhabited continents (a first for popes), and historic ecumenical break-throughs. But today he’s probably most remembered for his 1968 encyclical Humanae Vitae, which confirmed the Catholic Church’s long-standing teaching against contraception, abortion, and sterilization.

Outside of the Catholic Church (and, unfortunately, by a large number of people within the Church as well), the teaching of Humanae Vitae is considered absurd, if not gravely immoral and even dangerous for the world. Women’s liberation, population control, the war on poverty – don’t all of these causes need contraception, abortion, and sterilization?

I used to think so, at least regarding contraception (I was always against abortion).

When my girlfriend and I got engaged the spring of our junior year at Wheaton College (the “Harvard of evangelical schools”), we didn’t even discuss the possibility of having children early in our marriage – it was assumed that we’d use contraception.

Yet when we looked into what kind of contraception to use, we hit a snag: none of the methods seemed appealing. Something seemed “off” about all of them. This prompted us to want to do more research into Christian thinking about contraception in general. Though we were both evangelical Protestants and didn’t take seriously the idea of not using any contraception at all, we decided to give Humanae Vitae a read just to more informed about the spectrum of perspectives on the issue.

To our own surprise, just a few weeks later we were both firmly convinced that the use of contraception is gravely immoral, and mutually decided we would not use it. (Read our full story in my blog series “Why We’re Contraception-Free.”)

Five wonderful years of marriage and three beautiful children later, we can’t imagine living any other way.

I’ll note that we both later joined the Catholic Church, and that the Church’s stance on contraception was one contributing factor among many. But we were evangelical Protestants without any plans to join the Catholic Church when we first considered the issue of contraception.

Here’s what changed our minds:

1) The natural law argument makes a lot of sense

Natural what?

The “natural law” is just the moral law accessible to all people via their consciences (cf. Romans 2.15, et al.). The world has a natural order discernible by reason, and our bodies have an integrity, order, and dignity established by God that must be respected. So what’s the natural order of the sexual act?

By bringing the man and the woman together according to their sexual complementarity, the sexual act expresses and consummates their marital union. That same act is also naturally ordered to the procreation of children.

Contraception, on the other hand, attempts to block procreation, and it does so by distorting the act, having one of the spouses withhold a part of themselves, and thus disrupt the unitive meaning of the act as well.

But we should respect the order of nature, the natural meaning of the sexual act, our body, and the body of our spouse. Thus, contraception is immoral.

2) Contraception has had disastrous effects on society

In section 17 of Humanae Vitae, Paul VI predicts what would happen if contraception gained widespread acceptance. He warns:

(1) “[F]irst consider how easily this course of action could open wide the way for marital infidelity and a general lowering of moral standards…and especially [for] the young…”

(2) “[A] man who grows accustomed to the use of contraceptive methods may forget the reverence due to a woman, and, disregarding her physical and emotional equilibrium, reduce her to being a mere instrument for the satisfaction of his own desires, no longer considering her as his partner whom he should surround with care and affection.”

(3) There is “danger of this power passing into the hands of those public authorities who care little for the precepts of the moral law. Who will blame a government which in its attempt to resolve the problems affecting an entire country resorts to the same measures as are regarded as lawful by married people in the solution of a particular family difficulty? […] Should they regard this as necessary, they may even impose their use on everyone.”

Has contraception encouraged sexual promiscuity, particularly among the young? Definitely. Now that the use of contraception is expected, are men more likely to view women as mere sex objects to whom little responsibility is owed? No question. Have governments used contraception against their own populations? China’s brutal one-child policy is just one example of many in the last few decades.

Pope Paul VI was right.

3) Scripture condemns perversions of the sexual act

Genesis 38.1-10 tells the story of Onan. When his brother dies without leaving offspring for his wife Tamar, Onan marries her in order to help her have children (called a “levirate marriage“). Then Scripture says:

“But Onan knew that the offspring would not be his. So whenever he went in to his brother’s wife he would waste the semen on the ground, so as not to give offspring to his brother. And what he did was wicked in the sight of the Lord, and he put him to death also.”

Until the 20th century, this passage was read as a clear condemnation of coitus interruptus and, by extension, any alteration of the sexual act itself with the intention of preventing procreation.

Further, St. Paul condemns sexual acts that are “contrary to nature.” (Romans 1.26) This would also seem to rule out any changes to the sexual act that would frustrate its natural purposes, including contraception.

4) The Christian tradition was unanimously against contraception until the 20th century

Contraception has been around for thousands of years, and Christians have been against it from the very beginning.

Even as the Protestant Reformers rejected large chunks of Catholicism in the 16th century, the belief that contraception is gravely immoral was not a point of contention. Indeed, all Christian denominations taught that the use of contraception was gravely immoral – until the mid-20th century.

In the 1910s, atheist and racist eugenicist Margaret Sanger (founder of what is now known as Planned Parenthood) started campaigning against anti-contraception laws in the U.S. and intentionally pitted Protestants against Catholics in her rhetoric, saying that contraception was a “Catholic issue” – despite the fact that the anti-contraception laws she was campaigning against had been put in place by the Protestant majority. But her strategy worked.

The 1930 Anglican Lambeth Conference’s allowance for the use of contraception under a narrow set of circumstances was the first time any Christian denomination accepted its use under any circumstances. In the 1930s, as other mainline Protestant denominations accepted contraception, evangelical Protestants and Catholics found themselves fighting the culture war side by side. But in the 1940s and 1950s, most evangelicals capitulated and accepted contraception, too, leaving Catholics virtually alone on the issue.

When Pope Paul VI issued Humanae Vitae in 1968, he was simply upholding what Christians had always believed.

Now remember, Jesus himself promised to be “with [us] always, to the very end of the age,” (Mt 28.20); he said that, since He would build His Church on the rock, “the gates of Hades will not overcome it” (Mt 16.18); and he said he would send us the Holy Spirit, the “Spirit of Truth” (John 14.16-17, John 15.26, John 16.13).

So were Christians really fundamentally wrong in their understanding of sexuality and marriage until Protestants finally came to the truth under secular pressure in the 20th century?

5) Rejecting contraception is needed for a coherent sexual ethic that includes rejecting other sexual perversions

Though there’s no longer any serious cultural debate about contraception, we’re in the throes of a major debate about gay marriage.

While many Christians agree that the Bible condemns homosexual acts, are we able to explain why? Is it just arbitrary?

As long as heterosexual couples are morally permitted to use contraception and disregard the unitive and procreative meanings of sex, it’s not clear to me why homosexual acts would be wrong. But homosexual acts are wrong, and for the same reason contraception is wrong: both infringe on the natural purposes of sex, unity and procreation.

6) Humanae Vitae is far more nuanced than most people realize

But what if a woman needs hormones normally used for contraception to treat a medical condition? Paragraph 15 of Humanae Vitae addresses this kind of situation and says that as long as the treatment or procedure is needed for a legitimate medical purpose and is not intended for contraception (even if the contraceptive effects are foreseen), it’s fine.

And what if a couple honestly cannot handle another child? Are they required to keep on having more children? Of course not. For just reasons, couples can and should limit or space children. But instead of altering the sexual act, Pope Paul VI says that couples can intentionally have sex only during the woman’s natural period of infertility every month. And to help couples do this, he called on scientists to develop better methods for determining when the woman is fertile or not (which they have done).