Each year, Stacey and I work with couples preparing for marriage, and it always gets interesting when we open the conversation about sex.

We start by asking couples about their sexual activity and this is where it gets interesting. When we ask if they’ve talked about how to plan their family, invariably, the conversation goes from four people to two. The guy and I start to look like we’re watching tennis as Stacey and the woman converse back and forth.

Then, after we get a baseline understanding of where the couple stands, we reframe the conversation. It is here that we widen the conversation back out to four.

First, we identify the fact that the cultural language around family planning comes down a vocabulary of contraception: there are different methods and devices and medications that prevent pregnancy, and it is generally the woman’s realm to negotiate. The men have very little to contribute when the issue is framed this way–men are essentially cheerleaders, standing on the sideline.

In general, this vocabulary of contraception is used to make decisions about sexual activity and family planning based on fear–what the couple must avoid, what they cannot afford, what they cannot give.

We then offer alternative language for family planning that comes from our Christian tradition, which is built around a vocabulary of fertility. Instead of seeing fertility as something to be medicated, we encourage couples to cooperate with it. It is a miraculous gift, after all. God has entrusted to us a share in the ability to create new human life, and through a mind-blowingly pleasurable act on top of it all. Sexual activity and the safe birth of children is so often spoken of that we mistake it to be ordinary. It is truly the most extraordinary thing we can do as humans.

So, instead of manipulating this gift, we ask couples to consider working with it.

We don’t ask them to throw caution to the wind, and run willy-nilly into a future of continuous pregnancy and dozens of children. There is an alternative to contraception that is equivalent in effectiveness: Natural Family Planning. NFP is not the “rhythm method” of yesteryear–it is a way to scientifically document the progress of a woman’s cycle to determine the limited period of fertility. It is useful in both avoiding and achieving pregnancy, and, with proper training and commitment, has a 98% effectiveness rate. (Come to think of it, are there any family planning methods that work without proper training and commitment?)

We’ve used NFP for all of our married life, and the best part of it for me is that I am not a cheerleader on the sidelines. I’m in the game with Stacey, and we’re working together and on the same page. I know her cycle, often better than she does. Because of NFP, we share the gift of fertility every day, not just during nights in bed.

After all, fertility is nothing if not shared. There is no such thing as fertility for and by one alone, thank God. How boring would that be?

The vocabulary of fertility that NFP encourages has helped us to organize our family planning not around fear, but around generosity. When we talk about sex in our marriage, we talk about what we can offer, not what we must avoid. It is a conversation with a big horizon, encompassing not only our immediate desires, but also the hopes we have for our family.

Because NFP allows us to cooperate with this gift of fertility, we are reminded often of how extraordinary that gift is.

President Obama’s recent mandate that all health insurance plans include coverage for contraception, even in the form of sterilization and abortifacient drugs, was written in the vocabulary of contraception. There are significant questions about religious liberty at stake, which are distressing to me as a citizen. As a husband and father, however, I’m most distressed that health care in this nation will treat fertility as a problem to be medicated or manipulated.

The vocabularies of contraception and fertility form a language of love that is spoken by our bodies. Fertility is the most extraordinary capacity we have as humans, and it calls for respect and cooperation.