The Evolutionary Role of Religion and Its Impact on Fertility

Key Insight

Religion is a universal human phenomenon, with 84 percent of adults globally considering it an important part of daily life, a figure stable for years. Many scholars propose religion is an evolved behavior, wired into human neural circuitry, serving to alleviate the universal fear of death and confront selfishness arising from resource scarcity by promising an afterlife and linking control over selfishness to future life outcomes, thus promoting altruism.

This function is achieved by shifting individual focus from personal suffering to group belonging, allowing individuals to celebrate the tribe's reproduction. Émile Durkheim conceptualized this, stating 'God and society are one of the same...the god of the clan...can be none other than the clan itself', implying that worship of a god intrinsically reinforces care for the clan's defense, reproduction, and integrity, and fuels fear of other groups. For instance, an Iranian man was sentenced to death for 'waging war against God' by supporting a Kurdish rebel group, illustrating how threats to a divinely guided state are perceived as threats to its God.

Religion also directly impacts fertility. Psychologist Frank Sulloway's analysis of 86 societies found that both religiosity and religious beliefs independently predicted higher fertility, with the most religious individuals having 1.48 times as many children as the most secular. This trend persists even in low-fertility developed countries. Anti-abortion stances, weakly correlated with religious beliefs, also contribute to greater fitness, with pro-lifers having 1.45 times more children than pro-choice individuals, as religions often oppose abortion to multiply believers and assuage death anxiety.