Late in May, when the Centers for Disease Control released their preliminary report on birth numbers and rates during 2013, press coverage highlighted the good news it contained. The media found especially encouraging the nation’s continuing decline in teenage birth rates. These dropped 10% from 2012, and have declined an impressive 57% from their present-day peak in 1991. Others enthused about the increase in the number of births reported in 2013 over the previous year, and embraced this as evidence that the “baby recession may be at an end.” Reinforcing this optimism are pervasive hopes that the economic recession might finally be waning, and that young couples will respond by starting families.

Yet in their eagerness (finally!) to report that American birth rates might be veering from their recent downward trajectory towards European-style very low fertility levels, the media have generally exaggerated both the magnitude and significance of the increase in the number of births in 2013. This tendency is certainly understandable. The total fertility rate in the U.S. has hovered just below replacement level for two decades, and the overall birth rate declined steeply (by 8%) from 2007 to 2010 before assuming a gentler decline. Nonetheless, trumpeting an absolute increase of just 4,736 births from a 2012 baseline of almost four million as a major reversal is more hopeful than instructive. Observers might more accurately have noted that in 2013 the total fertility rate actually declined a percentage point from its already sub-replacement level of 1.88 in 2012.

The media’s emphasis on the tiny increase in the absolute number of births in 2013 obscures other, and more worrisome, developments.

The media’s emphasis on the tiny increase in the absolute number of births in 2013 rather than on that year’s “record low” general fertility rate not only dramatically overstates the magnitude and direction of U.S. birth trends, but also obscures other, and more worrisome, developments. (Indeed, at least one national publication eager to find good news in the CDC report mistakenly headlined the uptick in the number of births as an increase in the actual birth rate.) So too does the media’s focus on teen birth rates. For as welcome as is the continued decline in teen births, teen mothers are not the cohort currently driving America’s most worrisome birth trend: the stubbornly high incidence of nonmarital births.

The demographic largely responsible for the fact that two out of five babies are born to unmarried mothers is actually women in their twenties. As the report notes, 37% of nonmarital births are to women aged 20–24, and according to a separate report, the figure for twenty-something women overall is up to 60 percent. Babies born to unmarried teen moms, on the other hand, account for just 15% of the total, or a fraction of the 50% of nonmarital births for which they accounted in 1970. As one can see, media stories applauding the undoubtedly welcome decline in teen births—much like Mayor Bloomberg’s well-intended publicity campaign in New York City last year against teen pregnancy—deflect attention from the main drivers of America’s persistently high levels of nonmarital births.

According to the CDC, 40.6% of American births in 2013 were to unmarried mothers—a decline of just a tenth of a percentage point from the previous year’s figure (40.7%). Numerically, the country witnessed a reduction in the total of children born out of wedlock of fewer than 4,000 births from the previous year’s total of more than 1.6 million births. But the proportion of births to unmarried women has remained stubbornly high: it was less than 4% in 1940, and rose steeply beginning in the 1960s before moderating its ascent during the 1990s. It would be even higher than its present level if not for two countervailing trends.

The first is the much higher abortion rate among unmarried women; these women make up 85% of those choosing to terminate their pregnancy. And the second trend, to which the CDC report draws attention, is the growing share of children born to mothers over 30, a group that is more likely to be married. Indeed, in 2013 the birth rate of all women (married and unmarried) aged 20–24 was 81.2 births per 1,000 women—a figure that represents a 2% decline from the previous year’s record low. The birth rate for mothers aged 35–39 years during the same period, by way of contrast, increased 3% to 49.6 births per 1,000 women. Similarly, the 2013 birth rate for mothers aged 40–44, while smaller (10.5 per 1,000), increased by 2% over the previous year, as it has done consistently since 2000.

Significantly, it’s precisely here that the two consequential issues neglected by media coverage—namely the dramatic rise in the share of nonmarital births to women in their twenties, and persistently low total fertility rates—link up. For we know that women’s fertility peaks during their twenties, and that an increasing proportion of this cohort choose to have children even as they delay marriage or forego it altogether. As Kay Hymowitz and others have documented, women’s median age at first birth (25.7) is now lower than their median age at first marriage (26.5). Fully 48% of all first births are to unmarried mothers. And we also know that delaying childbearing, as a growing number of women likewise do, has an inescapably depressive effect on fertility rates. Given women’s declining fertility as they exit their twenties, postponing childbearing necessarily reduces the span during which mothers can conceive.

Older mothers suppress both the proportion of nonmarital births and the total fertility rate.

So these two neglected trends, which initially appear unrelated, are not just important, but mutually implicated. While women as a whole increasingly delay childbirth, a significant minority does not, but instead gives birth without first getting married. The result is that nonmarital birth rates remain persistently high, but are moderated by other women’s decisions to defer both marriage and childbirth. Older mothers thereby suppress both the proportion of nonmarital births and the total fertility rate.

Now, a decrease in the proportion of American children born to unmarried mothers, of course, would be a welcome development. Children who grow up in a stable, low-conflict household with their married biological parents enjoy, on average, considerably happier life prospects than their peers living in single-parent and cohabiting households. But reducing the age at first birth for married mothers, even assuming that we knew how, would be a considerably more nuanced affair.

This is because, as Hymowitz and others also inform us, there are good things that come from postponing marriage and childbirth. These include a lower likelihood of divorce and greater educational and professional gains for women and their families. And in any case, the increasingly prevalent “capstone” model of marriage that has generated these and other benefits, including mothers’ protection in the event of divorce, is not likely to revert to its “cornerstone” predecessor. This is especially true among more affluent and highly educated couples.

It is hard to see how, or whether, we could retain the benefits of the capstone model of marriage while maintaining healthy fertility rates and decreasing the prevalence of nonmarital childbearing. Nonetheless, if we are successfully to grapple with such conundrums, we’ll need frankly to acknowledge the complicated trends in family practices and fertility today. By providing indispensable data about these, the most recent CDC report immensely aids this task.  It’s now up to us unflinchingly to ponder them.

Brian J. Shaw is a Professor of Political Science at Davidson College.