Term used to describe low-income, uneducated (stupid) people in large families, due to their rapid breeding and the volume of their ignorance "chocking out" other lives around them.
See Harvey Danger:
"Been around the world and found
That only stupid people are breeding
The cretins cloning and feeding
And I don't even own a tv"
Also, see the movie, Idiocracy.
The average couple these days, they have one kid, maybe. That kid has one kid, and that kid has one kid. Three generations, total of three people. Those dandelions? They've got six kids. Those seeds have pretty much no chance. That family will fit in four generations in the time it takes the "average" folks to do three generations. Each of them will have six kids, who'll have six kids, who'll have six kids. That's one smart person for every 86 dandelion idiots in 60 years. We're so screwed.