“There are a thousand reasons not to have a baby,” write Candice and Steve Watters in Start Your Family. “But in deciding against children, or even in just deciding to wait a little longer, you risk missing out on a miracle—a larger-than-life, inexpressible joy.”

It’s a fascinating commentary on modern American Christianity that we need to be persuaded of the value of childbearing. This is perhaps the only area where I have any mild rebuke to offer young Christians who ask me for life advice. In practically every other area, likely as not their faith is more zealous, their lives more pure, their walks more resolute. But when it comes to childbearing, many of them fall into the trap of thinking this must be decided by reason and cost-benefit calculation rather than governed by faith. Rather, faith becomes an afterthought, a reserve parachute once the calculations have worked themselves out in favor of stepping judiciously from the airplane.

That image of a parachute jump is apt, I think, just as the Watters employ a bungee-cord metaphor to describe their leap into parenthood: “Something as grand and miraculous as a baby goes beyond the realm of calculated rationality into the realm of faith and risk taking.”

The reason calculations don’t work is fairly straightforward and perhaps unexpected, which is what I try to explain to young Christians who ask my advice. The bottom-line is that the calculations don’t add up. You’re never ready. You never have enough money or time or security or courage. What’s more, you can’t begin to count the costs. Sure, you can see in the tired eyes of your friends who are parents and hear in their stories tension, worry, and deteriorated sex lives, all of which are some of the costs of young children. Likewise, you can hear them describe the entirely unexpected joy of loving a baby. The numbers you scribble in the credit and debit columns are but faint reflections of the numbers a parent knows to put there. The cost is greater than you think. The joy is greater than you know. And you’re never ready for either.

This is why I tell young Christians to have babies. First, because it is a blessing crafted by a Creator God, that we might also participate in creation that leads to loving communion. But also because we need those sorrows just as much as we need the joys. That’s not a popular message from some pulpits, but the sorrow of parenting, just like the sorrow of being married, is an important part of our walk. Each requires us to put others above ourselves. The naive view of marriage, as of parenting, is that if we do everything right, these relationships will bring us tremendous joy. The reality is that even if we were to do everything right—which we won’t—they are still likely to bring us heartache. The heartache of dashed expectations, of self-sacrifice, of rejections large or small.

The notion that we are entitled to live without these experiences, indeed, that we can have any sort of sanctification without them, is a subtle lie that penetrates too many places where it ought to be refuted. This is why, I think, so many young Christians are inclined to wait until “the time is right” to have children of their own. The time became right when they got married. Unless their view is that the chief end of marriage is to entertain and please the husband and wife, in which case no time will ever be right.