I'd be interested to know their sources. All of the numbers that I could find from the Census Bureau seemed to more or less agree, but I'm not sure that they're controlling for factors like sexuality, which I have a feeling affects the statistics here in SF quite strongly, and non-traditional relationships. Particularly, I'd like to know what, precisely, they mean by 'single'. Until then, it's difficult to advance any theories.

As a wild guess, though, I'd advance the theory that men are more likely to pull up stakes and abandon their social networks and move to a new place, and that the recent decades of stronger than national average economic growth on the west coast has led a lot of them to move here. As a caveat, I am guessing that these numbers are overstated, so it would only take a slight difference in behavior to explain the numbers.

There's no magic bullet here. But my guess is that Evan's remark would count for some part of an r value. He's right too, how "single" was measured is unclear at least with a quick look. I also find the Boise, Idaho area weird, because there are opposite colored dots in more or less the same place. I'm interested as well in the sampling methodology for this study, or where the data was mined from.

I'd guess that the larger number of single women in the South is due to the military pulling out a large number of single men and shipping them out of the country (unless the census counts their home rather than their present location, in which case my theory is bunk).

I'm pretty sure the census does count soldiers' home rather than where they're stationed, but some of those soldiers, especially if they have families, just move into the city that their base is in.

My guess on explaining the gender ratio: The dominant industry in a city can explain part of it. E.g. software work attracts men, and this is pulled out of my butt, but I suspect there are more men than women immigrating illegally to border states. (What with the sort of work illegal immigrants do often being hard physical labor, plus women may stay home to deal with small children.) Whereas the female-heavy publishing industry is largely based in New York City. This theory doesn't do much to explain Boston or Chicago or Philly or DC, though. Does politics attract more women or men? And aren't women overrepresented among law students?

Women are overrepresented among college students, as well.

Well, that would help explain Boston.

Men, especially the married kind, die younger. The south is older: more single honies.

I was just talking this weekend about the predominance of single women in NYC and lack of single men. I thought it might be BECAUSE of Sex and the City. I feel like NYC is a hard place to live for a number of reasons. And yet young single women come from all over and tough it out because they want to BE Carrie Bradshaw. If you watch the men from Wall Street pile on to the Jersey ferries, Metro North and the LIRR every night ... it makes me think that they would rather make their money here but live elsewhere. Nobody in pop culture has glamorized the idea of a guy struggling to pay rent in order to stand in lines at a hip new bar and pay a fortune for tiny dinner portions.