Imagine a world where a brave array of new technologies has proliferated to meet our human needs by taming nature — yielding a vast increase in wealth, leisure and education.

Instead of scrimping like our ancestors at the mercy of forces beyond their ken, we have attained a noble’s sovereignty. Vast swathes of our lives are planted not with the starches of grim necessity but the fruit of our free choice.

Human life has begun to seem like an adventure.

Looking back at the sufferings of our grandparents, we almost doubt that their lives were fully human. We might admire their fortitude, but we certainly don’t wish to share the toil and tears that lined those black-and-white faces in those yellowed photos.

We glance at corners of the world where people still live as our forefathers did — and the scenes of poverty shock us. What is more, those folks are striving as fast as they can to join the rest of us. Soon the whole world will live as we do.

Alas, a serpent got into the garden. A technology fundamental to all this progress has dangerous, incalculable side effects.

At first, the signs were subtle and only appeared to experts. But, as time went on, the harm began to be obvious. Our carefully engineered techniques were disrupting the ecology. Resources became suddenly scarce. Exquisitely balanced biosystems started to fragment. Once-mighty natural forces began waxing feeble. Thundering rivers ran dry.

It seemed that the golden goose might be choking to death.

Experts explained why all this was happening, and the highest authorities offered a sobering diagnosis: We had overstepped the bounds of what nature would take at our hands. By subjecting the forces of life on earth to our inexhaustible wish list, we had threatened their viability.

We would have to go on a diet. We would need to step back, to renounce some of the control we had seized, and try to subsist in balance with the rest of nature again. We could still control our environment and plan our lives.

But to do this without poisoning our world we would also have to control ourselves, to act in careful harmony with the forces we wished to influence — rather than riding over them with a technological steamroller. It would mean living again in certain ways as our ancestors had.

Of course, there were dissenters who won popular praise by assuring the world’s consumers that the alarmists’ fears were misplaced. There was no need to worry about the mounting side effects of man’s technologies.

The resources that were depleted could be replaced; the biosystems that died had never been really essential; the freedoms we’d learned to treasure were too important to surrender.

Maybe the "authorities" weren’t really on the side of human freedom anyway — and it was time to find a new set of authorities; the dissenters modestly offered their services, and millions decided to follow them — creating a deep split of opinion between those who believed that a crisis existed and those who flatly denied it.

There was no room for compromise, so the two sides kept talking past each other, inventing ugly phrases to impugn each others’ motives.

How does the story turn out?

The above is not the story of climate change, but of the sexual revolution. The key technology in question is artificial contraception, and the ecology that is threatened is that of the human family.

It seemed once that the resources of nature were so inexhaustibly vast that they must be immune to our technologies; likewise, the institution of marriage and the family seemed too deeply rooted in human nature to be threatened by a few tweaks here and there.

Those who warned against each successive reform (laxer divorce laws, birth control, taboo-free premarital sex) as a threat to human marriage appeared as hysterical alarmists. Nothing as vast, ancient and primal as the heterosexual family was really fragile.

Surely the sheer vitality of human nature would preserve the "natural family" for the vast majority and keep the human race growing, even as our reforms made life more bearable for outsiders. One might as well worry that human beings could poison all earth’s air or kill off the life in its seas.

Now, of course, the doomsayers are getting some credit. Fewer and fewer young couples bother to marry at all, and a shrinking percentage of them will stay together.

Marriage has shrunk to such a pale ghost of itself that it can be blithely … redefined. Evermore, children are raised by that impoverished shard of a family, a single mother battling to her maximum limit to rear her young.

The birth rate is plummeting far below replacement levels … everywhere. The melting started with icy places like Japan and Russia. Then it jumped to Canada, Germany, Italy, even Spain. Then the United States.

Now birth rates are halving in Mexico. Each place that we imagine will make up for the birth dearth succumbs to the trend in turn.

The next great war over which human lives are sacred will center on the elderly — as the generation that embraced the pill and abortion ages ever more expensively in hospitals that their dwindled ranks of grandchildren cannot afford.

Those who did get born despite all these brave innovations, who scramble to support their own offspring in lands where children are scarce and barely supported, will look to the wrinkled rebels who left behind this mess with something less than the piety of Aeneas. There is some justice on earth after all.

Anyone who predicted this outcome in 1968 would have been dismissed as a fevered crank. Of course, that is what happened to Pope Paul VI. He warned in Humanae Vitae that new technological means of helping married couples plan their families would open a "wide and easy road towards conjugal infidelity and the general lowering of morality," a loss of "respect for the woman" and her reduction to "a mere instrument of selfish enjoyment" (17).

The Pope also noted that nothing would "stop rulers from favoring, from even imposing upon their peoples," the dictates of population control. So he called on us to "recognize insurmountable limits to the possibility of man’s domination over his own body and its functions" (21).

It is deadly to a man’s good name to be too right too soon. Paul VI and the other authorities — Scripture authors, Orthodox rabbis, Church Fathers, reformers like Luther and Calvin and every Christian church until 1930 — were right to warn us that some liberating theories and technologies cut too deep, too close to the roots of life.

The vast, compelling attractions of love and sex were given their strength precisely to drive us to do something hard and dangerous: to commit ourselves for life, to bear and nurture children. By cleverly splicing away the pleasure from the effort, we have done for sex what cocaine does for the brain. Now, modern men act like those rats that starve themselves in the lab, pushing the "pleasure" lever instead of the one that dispenses food.

John Zmirak is author of

The Bad Catholic’s Guide to the Catechism

and blogs at BadCatholics.com.