What I heard made me think twice about using the pill. It also led me on a journey that shifted my thinking about sex, my body, marriage, and our responsibility to children.

The first time I discovered there were legitimate reasons to not use the contraceptive pill, I was in my mid-20s and had just gotten engaged. A married friend handed me a cassette tape entitled, “Contraception: Why Not,” featuring a talk by a Catholic professor named Janet Smith.

“You should really check this out,” he said. Since I was producing a radio show at that time, I assumed he thought Smith would be a good guest. But when he added, ‘This really changed our thinking about birth control,” I remember thinking, “What could a Catholic professor possibly say about birth control that I need to hear?”

But I took it home and ended up listening to the tape over and over again. What I heard not only made me think twice about using the pill, it also led me on a journey that began a shift in my thinking about the purpose of sex, how I viewed my body and what I put into it, and my understanding of marriage and our responsibility to children.

I remember being so excited about what I learned that I wanted to share it with anyone who would listen, so, of course, I started with my fiancé (a devout Baptist). I still remember the shocked expression on his face the first time I asked him whether he was open to “having as many kids as God wants us to have?”

On the recording, Smith made a mostly academic case against birth control but also shared some of the Catholic Church’s teaching on married sex. I wanted to learn more, so I ordered some information from a Natural Family Planning (NFP) group I found online. The packet that came in the mail included a small copy of “Humanae Vitae.” What I read there, and later in Pope John Paul II’s “Theology of the Body,” left me in tears.

“Humanae Vitae” affected me in three main ways. I’ll share them.

1. I Learned More About How the Pill Hurts People

“Humanae Vitae” led me to do more research on the negative side effects of the Pill, which convinced me to reject chemical birth control and to embrace more natural methods.

I was really bothered that in 20-something years of growing up in a Christian community, I had never heard anything negative about the Pill—not in the Pentecostal church we attended when I was a child, nor in my Baptist-run high school, or even at my Presbyterian college.

Sure, I’d heard from several friends and family members that the Pill gave them headaches or caused them to gain weight, but no one had ever voiced any moral qualms, or otherwise, about birth control. It was assumed that when I got married (since I was saving sex for marriage), I would get on the Pill, just like every other woman I knew.

As a result of being introduced to “Humanae Vitae,” I sought out an NFP-friendly OB/GYN, learned more about the Billings Ovulation Method, and eventually began charting my cycle. Although my husband and I did not end up following NFP religiously, we did use the Billings Method to get pregnant with our children.

2. ‘Humanae Vitae’ Empowered Me with Knowledge About My Body

“Humanae Vitae” also empowered me with knowledge about my body and how it is perfectly designed to work in creating new life. Charting my cycle and learning about the fertile and infertile phases were empowering to me as a woman. By paying attention to my body’s natural patterns, I knew when I was most likely to get or not get pregnant.

This also helped me be aware of any changes that might affect my health. I credit NFP with the fact that we never had any problems getting pregnant, even though we got married later in life and started “trying” in our 30s/mid-30s (I was 35 when I had my youngest).

3. Deepened My Understanding of Sex, Marriage, and Children

Finally, “Humanae Vitae” expanded my understanding of sex, marriage, and children as a sacred part of God’s creative order. Reading “Humanae Vitae” for the first time, I felt like a thirsty person gulping down a glass of water. I had never heard marriage described in such ethereal terms.

It began by emphasizing that marriage is not “result of blind evolution of natural forces.” Rather, it is a “wise and provident institution of God the Creator.” I was particularly struck by the idea that through marriage, a husband and wife are “cooperating with God in the generation and rearing of new lives.”

As someone raised by a single mom in an extended family where divorce was common, I really longed for this vision of marriage as a holy institution where couples are working with God to have and raise children.

As for how “Humanae Vitae” defined sex, I had never heard it described as a “divine act,” nor had I been taught that it was equally about uniting a husband and wife and creating new life. Thus far, my understanding of “responsible parenthood” was having as many kids as you wanted and could afford within marriage.

But “Humanae Vitae” defined responsible parenthood as naturally welcoming to any new life that results from the sexual union, noting that “each and every marital act must of necessity retain its intrinsic relationship to the procreation of human life.”

‘Humanae Vitae’ gave me a vision of married sex to aspire to by presenting it as something beautiful, sacred, and consequential.

I was not sure how this vision of parenthood would work in my future marriage, and whether I could even uphold this ideal in practice. Still, “Humanae Vitae” gave me a vision of married sex to aspire to by presenting it as something beautiful, sacred, and consequential. In other words, sex is about more than the partners involved; it is about the children that act may produce and our responsibility to those children.

This new way of thinking about sex was radically different from the secular vision that said sex was mostly about self-fulfillment and pleasure. But it was also different from what I’d learned in the Christian community where I grew up.

Although I’d been taught that God created sex and that it belonged in marriage, most of this centered around a list of “dos” and “don’ts.” There was no theology of sex, no attempt to articulate a heavenly vision that could compete with the secular vision—or at least not that I had ever heard (Later, I discovered Protestant writers, like Nancy Pearcey, author of “Love Thy Body,” who present a holistic Christian view of sexuality.)

As a Protestant woman whose vision of sex, marriage, and parenthood was radically changed by “Humanae Vitae,” I am proud to join my Catholic sisters and brothers in celebrating its 50th anniversary this week. Along with leading me to make healthier choices about what I put into my body, through “Humanae Vitae” I gained a richer understanding of and appreciation for the sacredness of sex, the blessings of children, and marriage as an institution worth preserving.