By all accounts both President Barack Obama and his likely challenger, former Massachusetts Gov. Mitt Romney, are ideal family men, devoted to their spouses and their children. But support for the two men could not be more different in terms of the electorate’s marriage and family status.

An analysis comparing the results of the 2008 election and the most recent Gallup surveys with data by demographer Wendell Cox shows a remarkable correlation between the states and regions with the highest proportion of childless women under 45 – the best indicator of offspring-free households — and the propensity to vote Democratic. Overall, the most child-free regions were nearly 85% more likely to vote for Obama in 2008. And according to the most recent Gallup survey, they are similarly inclined to vote Democratic today.

At the top of the list, with 80% of its women under 45 without children, stands the rock-solid blue District of Columbia. Just behind that taxpayer-financed paradise the six states with the highest percentages — Massachusetts, New York, Rhode Island, Hawaii, Vermont and California — also skew Democratic. In each of these states the percentage of childless women exceeds 55%.

The highest percentage of offspring-free women under 45 can be seen as well in such Democratic metropolitan areas as Boston, San Francisco, Los Angeles, San Diego and New York In each of these metropolitan areas the percentage of childless woman reached a minimum of 60% well above the national average of 53%. In the urban cores of these regions the percentage can approach Washington’s 80% figure. To a large extent, childlessness correlates with high density and a less affordable housing stock.

The top child-bearing regions are almost all deep-red Republican, both in 2008 as well as today. The top five child-bearing states — Mississippi, Idaho, Wyoming , Oklahoma and Arkansas — all generally tilt toward the GOP. So do the metropolitan areas that have the lowest percentages of childless women: the Texas metros of Dallas-Fort Worth, San Antonio and Houston, Mormon stronghold Salt Lake City and Memphis. The next five include right-leaning Indianapolis, Charlotte, Louisville, Riverside-San Bernardino and Oklahoma City.

These numbers would be more striking if not for the somewhat higher propensity for child-bearing among African-Americans and Latinos, two core Democratic constituencies. As other surveys have shown, Republicans gains in recent years have come largely from married white families. In contrast, Democrats have lost the support of married people overall since 2008, even while gaining among the unmarried. If Republicans can lose their obsession with opposing homosexual families, they might even garner additional support.

A growing part of the Democratic base — aside from ethnic minorities — consists of white, childless couples and, in particular, single women. There’s much good news for Democrats here. According to the pro-Democratic advocacy group Women’s Voices, Women Vote, almost two-thirds of this demographic group voted for John Kerrey in 2004; in 2008 they went for Obama by nearly 70%. In 2010, a generally unfavorable political climate for Democrats, unmarried women helped power Democratic victories, particularly in Colorado and California, in the latter case against female Republican candidates.

Demographically, at least in the short and even medium term, betting of singles and the childless couples seems like a no-brainer. In the past 30 years the percentage of women aged 40 to 44 who have never had children nearly doubled to 19%. At the same time singletons of both sexes are on the rise, numbering over 31 million strong today, up from 27 million in 2000,a growth rate nearly double that of the overall population.

The increasing role of the childless may already be shifting the Democratic Party toward the kind of post-familalistic secularism generally associated with Europe or parts of East Asia. This could partly explain why the Obama Administration has been so willing to challenge the Catholic Church — a traditional home to many working class Democrats — on the issue of offering contraception to its employees. Simply put, in Democratic calculations, secular singletons may now outweigh religious Catholic Democrats.

The importance of singlehood and childlessness is amplified by location. The greatest bastions of non-families are found in the centers of the country’s media, cultural and intellectual life. Single households already constitute a majority in Manhattan and Washington, and they are heading in that direction in Denver, Seattle and San Francisco.

The growing self-confidence of these post-familial constituencies is evident in recent articles and books hailing not only the legitimacy but even the preference of this lifestyle option. Kate Bollick’s much celebrated and well-argued portrayal in the Atlantic of attractive matchless, and childless, 40-something females celebrates the coming of age of this new perspective on family life.

Bollick , citing the degraded condition of today’s males, openly embraces “the end of traditional marriage as an ideal.” One of her heroines, California psychologist Bella DePaulo, dismisses the traditional family unit as a kind of mental malady she labels “matrimania.” Oh well, there goes the primary basis for four thousand years of civilization.

The Atlantic piece serves as a kind manifesto for this key emerging Democratic constituency. But it’s not just single women now swarming into the Democratic Party. NYU Professor Eric Klineberg’s recent ode to singleness in the New York Times follows a similar narrative, but has room for left-leaning male singletons as well. This trend is even more pronounced in demographically disintegrating Europe, a fact that only increases its appeal to the sophisticated denizens of the single zone.

Are there any risks to Democrats — and advantages to Republicans — in this new post-familial tilt? Author and New America fellow Phil Longman argues that in the long run the “greater fertility of conservative segments of society” could allow the palpably brain-dead GOP to inherit the country. Childless singletons may be riding high now, he writes, but as non-breeders their influence ends with their own lifespans.

To win the future, according Democratic activists and millennial chroniclers Morley Winograd and Mike Hais, Democrats must all appeal to the next generation of families. Many of today’s childless millennials are still under 30 and plan to have kids, according to Hais and Winograd’s survey research. Reflecting their own experience with divorce as children, 50% consider being a good parent their highest priority in life. A strong plurality also see themselves ending up in the suburbs.

That means Democrats could pay a big price for disdaining homemakers, the often unaesthetic chores of child-raising and particularly suburbia, because that’s precisely the place where many of today’s urban millennials will likely end up in the next decade.

To address the future millennials, Democrats don’t need to adopt the often Medievalist views of their Republican rivals. But they will have to craft a message that appeals to a demographic that looks, at least somewhat, like the current First Family.

This piece originally appeared in Forbes.com.

Joel Kotkin is executive editor of NewGeography.com and is a distinguished presidential fellow in urban futures at Chapman University, and contributing editor to the City Journal in New York. He is author of The City: A Global History. His newest book is The Next Hundred Million: America in 2050, released in February, 2010.

Official White House Photo by Lawrence Jackson.