Thread by @Burnest137

Where did all the babies go?

Across nearly all of human history, sex was an extraordinarily high cost, high risk activity. It carried the risk of pregnancy, social consequences, abandonment risk, reputational damage, and profound resource burdens if a baby was conceived.

For women, reproduction required immense biological investment and risk; for men, the risk of uncertain paternity shaped strategy and behavior. Marriage norms, courtship rituals, religious prohibitins, family involvement, emerged as stabilizing mechanisms around those risks.

Sex was costly, and because it was so costly, societies developed structures to manage its hidden risks. Cost produced caution, caution produced institutions.
Reliable hormonal birth control radically altered that cost structure. In ways that are notcurrently well understood

The pill did more than prevent pregnancy, it decoupled sex from reproduction at scale. In evolutionary terms, that represents a profound shift in incentives. When the reproductive consequences of sex are dramatically reduced, the behavioral landscape changes, in unpredictable ways

Pair bonding no longer has to precede intimacy, long term commitment becomes less necessary before sex. Male and female mating strategies, which evolved under conditions where sex and conception were tightly linked, now we live in a world where that link is removed

When you reduce the cost of a historically high cost behavior, the behavior expands and the cultural systems built around its cost begin to erode. You can see it in all the institutions previously held sacred by our ancestors.

Marriage norms, expectations of chastity, and strong monogamous enforcement mechanisms were not simply moral artifacts, they functioned as equilibrium stabilizers in a world where reproduction was the near inevitable outcome of sex.

When pregnancy is always a live possibility, men are incentivized to commit before intimacy, and women are incentivized to secure long term investment before reproduction. Families and communities have stronger reasons to monitor quantity and quality of mate selection.

When a biological tether weakens, so does the incentive that upheld those norms. The argument here is not that birth control is inherently harmful, but that removing biological friction also removes cultural scaffolding. Biological alteration always carries an evolutionary cost

From this perspective, several effects follow. If sex routinely precedes commitment, commitment becomes optional rather than foundational. Marriage ages rise, fertility declines, and long-term pair bonds weaken in prevalence or durability. Does this world sound familiar?

In a low cost sexual marketplace, competition intensifies, often concentrating attention and opportunity among a smaller fraction of highly desirable individuals. This can increase mating inequality, leading to male disenfranchisement and female dissatisfaction.

Ten minutes scrolling social media and these effects enter center stage. The first world face fertility rates below replacement levels. The large-scale decoupling of sex from reproduction changes the default trajectory toward family formation and it’s fundamental incentives

From an evolutionary standpoint, a culture that persistently suppresses reproduction, eventually, disappears. There are also more subtle possibilities. As hormonal contraception may influence mate preference by altering natural cyclical shifts in attraction.

If mate choice occurs under hormonal conditions that differ from evolved patterns, long-term compatibility could suffer. This illustrates a broader point, complex biological systems often generate unintended consequences when altered rapidly. Noice the change currently underway?

Modern contraception operates instantly, reshaping reproductive calculus within a single generation. Evolution cannot adapt in time. When ancient drives face powerful tech overrides, systemic changes ripple outward. We didn’t choose this world, but we have to face its waves.

The pill may be the biggest evolutionary rewrites in history, because it modifies incentives around the central evolutionary imperative. None of this negates the significant benefits of birth control, expanded autonomy, educational, career opportunities:

When the biological cost of sex approaches zero, the social equilibrium built around that cost collapses. We are living through the collapse, the question is, how do we respond? Climb the mountain of life once more? Or go extinct?

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