CHELSEA, Mich. – Kristi and Michael Burns have a lot in common. They love crossword puzzles, football, going to museums and reading five or six books at a time. They describe themselves as mild-mannered introverts who suffer from an array of chronic medical problems. The two share similar marital résumés, too. On their wedding day in 2011, the groom was 43 and the bride 39, yet it was marriage No. 3 for both.
Today, their blended family is a sprawling, sometimes uneasy ensemble of two sharp-eyed sons from her two previous husbands, a daughter and son from his second marriage, ex-spouses of varying degrees of involvement, the partners of ex-spouses, the bemused in-laws and a kitten named Agnes that likes to sleep on computer keyboards.
If the Burnses seem atypical as an American nuclear family, how about the Schulte-Waysers, a merry band of two dads, six kids and two dogs?
The typical American family, if it ever lived anywhere but on Norman Rockwell's Thanksgiving canvas, has become as multilayered and full of surprises as a holiday turducken — the all-American seasonal portmanteau of deboned turkey, duck and chicken.
Researchers who study the structure and evolution of the American family express unsullied astonishment at how rapidly the family has changed in recent years, the transformations often exceeding or capsizing those same experts' predictions of just a few journal articles ago.
"This churning, this turnover in our intimate partnerships is creating complex families on a scale we've not seen before," said Andrew J. Cherlin, a professor of public policy at Johns Hopkins University.
Yet for all the restless shape-shifting of the American family, researchers who comb through census, survey and historical data and conduct field studies of ordinary home life have identified a number of key emerging themes.
Families, they say, are becoming more socially egalitarian overall, even as economic disparities widen. Families are more ethnically, racially, religiously and stylistically diverse than half a generation ago — or even half a year ago.
"There are not just more types of families and living arrangements than there used to be," said Stephanie Coontz, a social historian at Evergreen State College in Olympia, Wash. "Most people will move through several different types over the course of their lives."
At the same time, the old-fashioned family plan of stably married parents residing with their children remains a source of considerable power in the United States — but one that is increasingly seen as out of reach to all but the educated elite.
"We're seeing a class divide not only between the haves and the have-nots, but between the I dos and the I do nots," Coontz said. Those who are enjoying the perks of a good marriage "wouldn't stand for any other kind," she said, while those who would benefit most from marital stability "are the ones least likely to have the resources to sustain it."
Yet across the divide runs a white picket fence, our unshakable star-spangled belief in the value of marriage and family. We marry, divorce and remarry at rates not seen anywhere else in the developed world. We lavish $70 billion a year on weddings.
In charting the differences between today's families and those of the past, demographers start with the kids — or rather the lack of them.
The nation's birthrate today is half what it was in 1960, and last year hit its lowest point ever. At the end of the baby boom, in 1964, 36 percent of all Americans were younger than 18; last year, kids accounted for just 23.5 percent of the population, and the proportion is dropping, to a projected 21 percent by 2050.
One change that caught many family researchers by surprise was the recent dip in the divorce rate. After many decades of upward march, followed by a long, stubborn stay at the familiar 50 percent mark that made every nuptial feel like a coin flip, the rate began falling in 1996 and is now just above 40 percent for first-time marriages.
