In the U.S. today, only 3 of 5 babies have married parents.

Listen to Cathy Young:

[the] 40% of all babies born in the United States . . .born to single women [is] up from 34% in 2002. Some sociologists believe we have reached a tipping point: the link between marriage and parenthood is no longer the norm. Why is this happening. . .? [A] difficult question. . .we ignore at our peril.

The powerful economic, social and cultural pressures that once pushed . . . people into marriage are gone almost completely. All that remains is romantic love - and refusing to marry your child's other parent is often seen as more honorable than marrying someone you don't love . . .

large numbers of men are alienated from family life and from the next generation.

Listen as well to Ari Armstrong:

the dramatic rise in out-of-wedlock births points to deep cultural problems. . . Out-of-wedlock births are largely a phenomenon of lower-class America. . . "Only 4% of college graduates have children out of wedlock."

The "percent of births to unmarried women" for "all ages" breaks down as follows:

All Races: 38.5
White: 33.3
Black: 70.2
Hispanic: 49.9

And listen to Rob Stein and Donna St. George:

60% of those who had babies between 20 and 24 were single, up from 52% in 2002,

The rate of babies being born to unmarried women in the United States is starting to look more like [Europe]. . . the percentage of babies born to unmarried women is . . . about 55% in Sweden, about 50% in France and about 44% in the United Kingdom.

Stein and St. George do zero in on the major problem with single-parent families:

studies have shown that children generally fare better when they grow up in stable households with two parents. "We know that babies and children do best with committed, stable adult parents — preferably married," said Sarah Brown of the National Campaign to Prevent Teen and Unplanned Pregnancy.

And Cathy Young as well points out:

there is abundant evidence that children generally fare better with two parents - and many children without fathers keenly feel their absence. . . a visiting dad is usually, even with best intentions, a pale substitute for day-to-day interaction with a father in the home. . .an intact marriage is still the most reliable way to protect the father-child bond. . . Giving up on the two-parent family as an ideal would be a sad defeat.

The Fragile Families and Child Wellbeing Study, a joint project of institutes at Princeton and Columbia, has several authoritative articles and papers documenting the importance of having fathers around, whatever the continuing romantic involvement between parents. Marriage, of course, works best to keep fathers in the home.

There’s one mitigating factor that cuts against the high percentage of out-of-wedlock births: about 40% of those births occur in households where couples are cohabitating. Not marriage, but better by far than true single-parent childrearing.