Key findings

• Twin studies suggest that religiousness is largely environmentally influenced in childhood and adolescence, but more genetically influenced in adulthood .

• Other research reports little to no heritability for adolescent religiosity, but moderate genetic, shared-environmental, and non-shared-environmental influences on adult religiosity .

• A study of adult male twins investigated current and retrospective religiousness and estimated genetic and environmental influences on religiousness across age .

• Research using twin and sibling data has found growing evidence that genetic or other biological factors may play some role in religious life .

What this does and does not mean

• The evidence supports partial heritability, not genetic predetermination .

• These studies should not be read as evidence for a single “religion gene” or for genes determining whether someone becomes Christian, Muslim, atheist, or religious in general .

• A plausible interpretation is that genes influence broader traits or dispositions that may affect religiosity indirectly, such as community orientation or desire for existential certainty .

• Heritability means that genetic differences help explain some variation between people in a measure; it does not mean an individual’s beliefs are fixed by genes .

Caveat

• The evidence is strongest for broad measures of religiosity, such as religious involvement, values, or orientation, not for specific doctrinal beliefs .

• Culture, family, education, life experience, social environment, and personal reflection remain major influences on belief .

So the careful answer is: studies imply that religiosity can be partly heritable, but not that belief is genetically predetermined .

Key findings

• Twin studies suggest that religiousness is largely environmentally influenced in childhood and adolescence, but more genetically influenced in adulthood .

• Other research reports little to no heritability for adolescent religiosity, but moderate genetic, shared-environmental, and non-shared-environmental influences on adult religiosity .

• A study of adult male twins investigated current and retrospective religiousness and estimated genetic and environmental influences on religiousness across age .

• Research using twin and sibling data has found growing evidence that genetic or other biological factors may play some role in religious life .

What this does and does not mean

• The evidence supports partial heritability, not genetic predetermination .

• These studies should not be read as evidence for a single “religion gene” or for genes determining whether someone becomes Christian, Muslim, atheist, or religious in general .

• A plausible interpretation is that genes influence broader traits or dispositions that may affect religiosity indirectly, such as community orientation or desire for existential certainty .

• Heritability means that genetic differences help explain some variation between people in a measure; it does not mean an individual’s beliefs are fixed by genes .

Caveat

• The evidence is strongest for broad measures of religiosity, such as religious involvement, values, or orientation, not for specific doctrinal beliefs .

• Culture, family, education, life experience, social environment, and personal reflection remain major influences on belief .

So the careful answer is: studies imply that religiosity can be partly heritable, but not that belief is genetically predetermined .