Until about 25 years ago, scientists assumed that religious behaviour was simply the product of a person's socialisation - or "nurture". But more recent studies, including those on adult twins who were raised apart, suggest genes contribute about 40% of the variability in a person's religiousness.

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Now, researchers led by Laura Koenig, a psychology graduate student at the University of Minnesota in Minneapolis, US, have tried to tease apart how the effects of nature and nurture vary with time. Their study suggests that as adolescents grow into adults, genetic factors become more important in determining how religious a person is, while environmental factors wane. (Drudge)