In December 1949, LIFE magazine published an article that, all these years later, still feels rather odd. Titled "The Fruitful Mountaineers," the feature made the argument that, in postwar America, "the chronic baby boom of a Kentucky county, denounced as a 'biological joy ride to hell,' [rolled] merrily along to replenish the nation."
In short, the article suggests, Leslie County, Ky., was (and who knows, perhaps it still is) largely populated by people who really, really enjoyed making babies, and—depending upon one's point of view—their vigor was either a positive omen or a harbinger of disaster for the nation:
The great U.S. baby boom which reached its squalling crest in 1947 [wrote author T. S. Hyland] is now on the downgrade. It has started sliding back toward the neatly rationed, two-to-a-family level that seems a cherished feature of the American dream of middle-class respectability. Only in one area does the boom heedlessly persist: in Leslie County, deep in the Kentucky mountains.
There is always a baby boom in Leslie County. In fact, its mountaineers are probably, in this respect, the busiest people on earth, multiplying at a birth rate about double that of the U.S. as a whole and equal to that of the swarming hordes of China and India. [But] the most striking fact about Leslie County is not how many babies its people have but how much they enjoy having them. In the two-room cabins along Hell-for-Certain Creek, Greassy Creek and Thousandsticks Mountain, the gospel of planned parenthood has fallen on deaf ears. . . .
While the Kentucky mountaineer has, on occasion, been praised as a proud, intelligent, independent member of the "Old American" frontier stock, he has also been damned as a degenerate, inbred, shiftless congenital moron. His proliferation has been called a "disgusting perversion of evolution" and (with equal venom) "a biological joy ride to hell."
By now, most readers will not only have caught a glimmer of the enjoyment that T. S. Hyland evidently got from reporting and writing "The Fruitful Mountaineers," but will also have begun to sense one of the key, unsettling crosscurrents of the article. Namely, Hyland's contention that, in the eyes of some people (purse-lipped New Englanders, for example), Kentuckian fecundity was hardly something to celebrate; instead, for many, it was a revealing emblem of the fact that the "wrong people" were procreating at an alarming rate, while the "right people"—bankers, lawyers and other ostensible paragons of probity—were having smaller and smaller families.
"The gist of the wailing," a biologist in Hyland's story noted sardonically, "is that the bad boys and girls reproduce too much and the good boys and girls too little."
Seven decades later, the terms employed when discussing the issue are perhaps more decorous than they were in the '40s: for example, not many people today speak or write (openly, at least) of "the swarming hordes of China and India." But often-heated conversations about the birth rates among different sectors of society ensure that planned parenthood, contraception, abortion and other contentious—and, for some, morally freighted—issues will remain topics of debate for as long as men and women in the U.S. and around the world stay fruitful and multiply.
Liz Ronk, who edited this gallery, is the Photo Editor for LIFE.com. Follow her on Twitter at @LizabethRonk.