That is why it is so important to properly identify the cause of fertility decline. And on this point, much of the media is failing us.

The New York Times is almost gleeful in its write-up of the most recent CDC numbers, noting that “some demographers say the precipitous drop of births among teenagers and women in their early 20s shows that women have more control over their fertility.”

The New York Times then calmly adds, “Women are still having children, but they are just having them later, the demographers say.”

While it is good that births to teenage mothers have declined, falling teenage birthrates are not the driving cause of declining fertility, and hoping women in their 30s will suddenly start making up the difference is a fool’s errand.

Fertility is declining because marriage is declining. It is as simple as that. Fewer women are getting married, and when they do, they are getting married later in life. Married women are about three times more likely to have children than unmarried women, so the fewer married women there are, the fewer babies are born. It is just math.

In 1970, when the total fertility rate was a healthy 2.48, well above the 2.1 replacement level, 61% of women of childbearing age were married, compared to 30% who were single. Today, those numbers are flipped. Just 37% of women of childbearing age are married, compared to 63% who are single. As a direct result, our total fertility rate today is an anemic 1.57.

Now, it is true that teenage births are falling. And that is a good thing. Births to unmarried mothers are falling, too, and that is also a positive development. But the overall decline in births is not due to falling birth rates among unmarried women. The underlying cause is the decline in marriage, which was partially covered up by a spike in unmarried births that is now returning to normal.

Births to unmarried mothers were a rare occurrence in the United States for most of our history. Through the end of the 1960s, just 10% of all babies born in the United States were born to unwed mothers. That number began to rise in the following decades, hitting 20% in 1983 and 30% in 1991, before peaking at 41% in 2008.

Since 2013, however, the percentage of babies born to unwed mothers has begun to slowly decline, falling back to 35% today. This year’s drop in teen births will only lower that number further.

This unwed-mother baby boom spanning from 1970 to 2013 helped cover up the steady decline in births to married mothers. Births to married mothers actually peaked at 3,336,000 in 1970 and have been falling ever since. Meanwhile, unwed births rose from just 401,000 in 1970 to a high of 1,726,000 in 2007, and have since fallen to 1,281,000 today.

The problem is not that married women are less likely to have children. Annual births per 1,000 married women have been largely consistent since 1985. The problem is that there are simply far fewer married women than there used to be. While the number of women of childbearing age has increased steadily from 41,812,000 in 1970 to 65,925,000 today, the number of married women of childbearing age peaked in 1990 at 29,790,000 and has been steadily falling ever since.

If we want to get back to replacement fertility, if we want our nation to continue into the future, we are going to have to reverse the decline in marriage.

And we do not need to return to the marriage rates, or the average age at first marriage, of the 1950s to get there. If we could simply get back to the marriage rates we had in 1980, hardly a year of patriarchal despotism, the United States could once again sustain itself demographically.

Getting back to a United States in which a majority of women of childbearing age are married will require significant political and cultural change. We have to treat marriage not as just one acceptable option on the menu of life, but as the central institution of civil society through which our desires for physical and emotional intimacy are channeled and transformed into productive, cooperative behavior.

The good news is that most young single men and women still want to get married. According to the Pew Research Center, 69% of never-married adults ages 18 to 34 say they want to be married someday. We just have to help them attain that dream.

The first step is economic. A pro-marriage agenda should make it easier for young adults to stand on their own feet. That means more vocational training, more apprenticeships, fewer pointless degree requirements, and a labor market that rewards work instead of credential inflation. It means policies that raise the wages and stability of working-class men instead of undercutting them. A man with a steady job, a future, and a sense of responsibility is more marriageable than a man bouncing between precarious gigs with no path upward. If we want more marriages, we need more men capable of supporting a family and more women confident that they can rely on them.

Second, we should stop punishing marriage in public policy. For decades, means-tested safety-net programs have been designed in ways that can make marriage financially irrational for lower-income couples. That is madness. The government should not tell people to marry with one hand while penalizing them for doing so with the other. Every marriage penalty embedded in the tax and welfare state should be identified and removed.

Third, we need to lower the cost of forming a household. Marriage is easier when rent is affordable, when starter homes exist, and when a young couple can imagine building a life together without signing up for permanent financial anxiety. Family policy cannot be severed from housing policy. A country that makes it difficult to afford a home will also make it difficult to form a family.

PUBLIC SECTOR UNIONS ARE MAKING BLUE STATES UNGOVERNABLE

Fourth, culture matters. A society saturated in pornography, marijuana, gambling apps, and a thousand other forms of algorithmic distraction is not neutral on marriage. It is anti-marriage. These industries do not cultivate discipline, fidelity, or ambition. They cultivate passivity. A serious pro-marriage politics would stop treating the vice economy as untouchable.

And finally, we need to recover the confidence to say that marriage is good. Not perfect. Not easy. But good for men, good for women, good for children, and good for the country. The way back is not nostalgia for the 1950s. It is building a 21st-century America in which ordinary people can once again afford commitment, trust each other enough to make it, and know that their culture and government are helping, not hindering, them along the way.