I’ve heard, and used the above insult on more than a few occasions, but I have no idea what it means. I assume it says something about your mother’s promiscuity, but I can’t make a connection.
Anyone know where this came from/what it means?
V.
Or at least her fashion sense. 
If I remember, Cecil actually has an article on this somewhere, but perhaps I am wrong.
Actually I do believe it is a prostitution reference…specifically that special brand of camp follower who catered to our courageous boys in the armed services. Think back to the Civil War when a good painor Union Army combat boots would indeed have been worth a pretty penny, and you can see how they might have come into the hands (or feet) of a prostitute or two.
Don’t think so. The term “combat boots” is of WWII vintage, I believe. Shoes worn by Civil War soldiers did not carry this appellation.
Anybody here ever seen the Li’l Abner comic strip? Remember how the granny in that strip wore combat boots? Remember the boots worn by Granny on the Beverly Hillbillies? Somehow, these boots came to be an emblem of southern poverty. I don’t know how. Maybe they were cheap to come by for people who couldn’t afford nicer shoes. (Army surplus, maybe?)
I think the insult in the OP just implies poverty.
The phrase came into general use some time before the late 1960’s. (I can’t give an exact date, but I heard it as a kid and, as noted above, “combat boots” and “army boots” were a WWII development.)
Prior to the cultural changes of the late 1960’s, no woman with sense would be found wearing such footwear (actual, working farmers excepted). Back in the days of spike heels, stiletto toes so narrow that some women actually had their small toes amputated to fit into narrow shoes, and similar displays of fashion, a woman wearing army boots (as Mammy Yokum did) was considered hopelessly unfeminine, not just unfashionable.
Among the fashion “rebellions” of the 1960’s, was the “army surplus” look when actual combat boots below dungarees or khakis showed up in classrooms all over the country. As different takes on fashion moved out into society, where women were no longer required to wear dresses at work and comfortable footwear was permitted in the office (including hiking shoes that can resemble combat boots–at least compared to pumps), the insult has lost its clear meaning to a generation raised outside the strictures of the 1950’s and earlier.
(Even today, I would wager that combat boots worn with a skirt or dress where the hem ended above the ankle would be considered, at best, “clunky.” Combat boots with a skirt that came to the knee would not pass any fashion judgment that I can think of.)
Hurrah! I love Yo Mama jokes because, on the whole, they are creative and very, very funny. So I’ll just share some of my favorite Yo Mama’s so fat…
Yo Mama’s so fat, when she dances she makes the band skip.
Yo Mama’s so fat, all the restaurants in town have signs
that say: "Maximum Occupancy: 240 patrons or Yo Mama.
Yo Mama’s so fat, when she ran away, they had to use all
four sides of the milk carton.
Yo Mama’s so fat, she can’t even jump to a conclusion.
Yo Mama’s so fat, she’s got smaller fat women orbiting around her.
Yo Mama’s so fat, when I climbed up on top of her last night, I burned my ass on the lightbulb.
Any more Yo Mama jokes…?
This doesn’t really have anything to do with “yo Mama”, but I read somewhere that around the time of the Civil War, the word “gay” was slang for being a prostitute. As for the combat boots, I always thought it meant that yo Mama dressed/acted/looked butch.
WWII GIs wore combat boots. GIs were referred to as “dog faces”. Ergo, “yo’ mama is ugly”.
I always assumed it meant something along the lines of, “Your mother’s feet are so big, the only shoes she can find that fit are Army boots.”
Okay… I admit… I surf the web on the job… I need to find amusement where ever I can… I found tons of amusement the “YO mama’s so fat…” string of jokes you posted! Thank you!
Sorry I’m not addressing the actual question, but I’m not an informed history buff.
My father explained to me that in the post WWII years, Army surplus stores abounded, and combat boots were some of the cheapest footware one could buy. Therefore, he interpreted the insult to mean that “your mother” is cheap at the expense of good taste.
I always knew it as “Your Mama wears combat boots from the Salvation Army”.
Just my .02
Rose
This Cecil column doesn’t answer the OP, but it does provide several more “yo mama” jokes.
I particularly like the Lonely Hearts Club one.
Many thanks, I also like the not that lonely lonely hearts club!
The phrase came into common use in WWI, when prostitutes would work the trenches, which were often muddy and difficult to traverse in anything other than combat boots.
:dubious: There were prostitutes in the trenches?
As an aside, Mr. New Person, could you tell me – genuinely curious – what could the SDMB do to make folks like you aware that you’re chiming in on a conversation that died eleven years ago? Snark not directed at you, but I think this board really needs to think of a solution to this.
I have wondered this about several zombies. Did someone do a search for this particular topic just so they could throw in something that was basically already said?
BTW yo mama’s so fat, when she hauls ass she gotta make two trips. 
I’m sorry, but I need a cite.
Yo mama wears combat boots - she’s butch, lesbian etc.
That’s how I always took the expression. This was decades before women soldiers in fatigues & boots were common. WWII military woman (WACS, WAVES) wore skirts, hose, and still retained a degree of femininity.
bschauer, welcome to the boards. However, we prefer that very old threads in GQ only be revived if significant new information is being added, not just to make a joke. For that reason, I am closing this.
Colibri
General Questions Moderator
PS. Those who wish to tell “Yo mama” jokes should do so in another forum.