Why do we pray? Research has thrown up some interesting answers.
Some pray out of habit, others out of fear of death, but new experiments have offered two surprising reasons people find God - sex and stress relief.
In an experiment, where men and women were shown dating profiles of attractive members of the same sex, they described themselves as more religious than people who don't feel as if they have to compete in the attractiveness stakes.
Meanwhile, another study found that thoughts of randomness push people toward God - but only if they can't attribute feelings of stress to some easily defined external factor.
Subjects were primed for random thoughts by being exposed to phrases containing words such as "chance", "haphazard" and "random".
"You can become more or less religious depending on the situation," New Scientist quoted Ara Norenzayan, a psychologist at the University of British Columbia in Vancouver, Canada, who was not involved in the studies, as saying.
Such fickle religious behaviour could be especially important as promiscuous students mature into monogamous adults, said Douglas Kenrick, a psychologist at Arizona State University in Tempe, whose team uncovered the link between mating and religion.
To probe the relationship between sex and God more explicitly, researchers presented hundreds of students at their university with dating profiles of highly attractive men or women, then probed them about their religious beliefs.
A control group of 1500 students merely filled out the religion survey.
Men and women who looked at attractive members of the same sex reported stronger religious feelings than those who checked out prospective mates or just filled in the survey.
They were more likely to say "I believe in God" and "We'd be better off if religion played a bigger role in people's lives."
"It's an interesting and surprising phenomenon," says Kenrick.
He speculated that people ramp up their belief in a system that tends to enforce monogamy when they're confronted with fierce sexual competition.
It might have been expected, for example, that people are more religious when they are young, when they have to compete more for sex.
"People actually switch on and off their religious beliefs over their lifetime to fit the current mating context they're in," he added.
The study has been published in Sex: Journal of Experimental and Social Psychology.