We’ve all seen the headlines-more than half of babies born today in America to women under 30 are born out of wedlock.

The New York Times put it this way: “It used to be called illegitimacy. Now it is the new normal. After steadily rising for five decades, the share of children born to unmarried women has crossed a threshold: more than half of births to American women under 30 occur outside marriage.”

So why does this matter so much? How worried should we be?

Very, very worried. Simply because kids born to single women or kids born to couples who have not made the commitment of marriage lack both the emotional and the financial security of children born to a married mom and dad.

It is scarier than we imagine! The breakdown of families is creating a whole new underclass in America-almost a third of our population that doesn’t attend church, doesn’t get married or make real family commitments, doesn’t finish high school or attend college, doesn’t work full time, doesn’t eat right or exercise and thus is seriously overweight, and essentially doesn’t believe in the ideals that this country was founded on.

America is more divided right now than it has been at any time in its history since the Civil War.

And the main divider is not race, or gender, or sexual preferences, or the Tea Party or the Occupy movement or even basic economics and income (Each of these is divisive, but none of them are the main divider.)

The great divider is a complicated malaise that can best be defined as the breakdown of families.

In his new book Coming Apart, Charles Murray compares two “tribes” of white Americans, age 30 to 49. (He stays with whites in his comparison, because he wants to focus on other factors than race.) People in the top tribe (about 20% of the population) have at least a bachelor’s degree and work in higher paying professional or white collar jobs. People in the bottom tribe (roughly 30%) have no more than a high school diploma and work in blue collar or low skilled jobs.

In the top tribe, about 85% are married; in the bottom tribe, 48%. In the top tribe, 40% don’t go to church or profess any religion; in the bottom tribe, the figure is 60%. In the top tribe, 12% are either unemployed or work only part time; in the bottom tribe it is over 20%. In the top tribe, 6% of kids are born out of wedlock; in the bottom tribe, 44%.

The trends over the last 50 years are even more worrisome than the numbers themselves. Crime rate in the top tribe has stayed flat since the 60’s while it has sextupled in the bottom tribe. Unemployment has gone up 3% in the upper tribe since the 60’s while it has doubled in the bottom tribe. Secularism (no religion) has gone up twice as much in the bottom tribe than in the top. Nonmarital birth has doubled in the top tribe but gone up by 700% in the bottom tribe. The great divide, in other words, is getting wider.

These numbers and trends are quite different from most of our prevailing assumptions. For a long time the common belief has been that lower economic classes were more religious and more traditional than their upper class counterparts. It turns out that it is just the opposite. Prosperity and education parallels and seems to predict a higher likelihood of having traditional families and values.

But again, the most troubling thing is the ever widening gap between these two social tribes of Americans. We are becoming polarized into a two-caste society. The top 20% is much more prosperous and much more oriented to traditional values while the bottom 30% is less likely to get married, less likely to go to church, less likely to be active in their communities, more likely to watch TV excessively, more likely to be obese. And there is less and less interaction between the two tribes. People are increasingly likely to live, work, associate, and stay among their own tribe. (David Brooks of the New York Times suggests that the solution is for members of the top tribe to live and work together with the lower tribe for a couple of years in order to “spread out” the values, practices and institutions that lead to achievement.” (Sounds a lot like what Mormon missionaries do during their two years of service.)

The real question of course, is cause and effect. Does the upper tribe have its values and strong families because it is more educated and prosperous, or is it more educated and prosperous because of its values and strong families?

We, of course, vote for the latter. Strong families and values are the basic cause. Everything else is effect. When couples marry and make commitments to each other they greatly increase their chances of economic well-being. When children are born in wedlock their opportunities and their likelihood of professional success skyrockets. And when families work and play together and prioritize each other, neighborhoods and communities strengthen, economies improve, less government and fewer “safety nets” are needed and greater collective prosperity results.