Religious and non-religious people alike are full of opinions about the effects that a religious upbringing does or does not have. Thankfully, real evidence is finally becoming available to tie these discussions to reality, and a new study suggests that religious kids are less giving and more punishing than secular ones. This sounds terrible on its face, but its complicated, and so is the current bigger picture as to whether you should raise your kids religious.
Psychologists at the University of Chicago led by Prof. Jean Decety looked at data on over a thousand children from various countries (Canada, China, Jordan, South Africa, Turkey, and the United States) to assess apparent differences between the religious and non-religious ones on several dimensions. The children, who ranged from age 5 to 12, generally became more likely to share stickers in a game designed to test generosity as they grew older. But religious (Christian and Muslim) remained less likely to share their stickers than the non-religious kids.
In another part of the study, children watched scenarios that displayed other children colliding with each other, sometimes on purpose but sometimes accidentally. The experimental participants were asked about how "mean" the fictional kids were, and whether they deserved to be punished. Again, there was a difference in the Christian and Muslim kids, who judged the pushers harshly and recommended stronger punishments.
Previous evidence suggests that religious kids display more self-control and react better to discipline, though the value of these traits is sort of in the eye of the beholder (maybe some parents want their kids to place less trust in authority figures, or to not have to restrain themselves at such a young age). The alleged better mental health enjoyed by religious kids and adolescents is unfortunately based on data reported by parents. This doesn't mean that the claim isn't true, but it does mean that less biased research is necessary to prove it.
Another study shows that religious children have a harder time distinguishing fantasy from reality than secular children. This sounds terrible, but since the study was done on kindergartners, the children were just beginning to reach this developmental milestone at all and they have plenty of time to sort things out before adulthood. A follow-up study on adults would be much more damning indeed.
All of that being said, the vast majority of religious children are not literally being "abused" by their upbringings (contrary to the protestations of famous atheist Richard Dawkins). We devalue that serious term when we use it to describe situations in which we merely disagree with our parents in retrospect. And after all, the most atheist and liberal parents around can still manage to impart plenty of other emotional baggage by the time their children have left the nest.
The benefits of religion may show up later in life, and/or in ways that the studies mentioned above haven't captured (like feeling as if you have meaning in life, or helping you to die a peaceful death). I can understand wanting your child to grow up to be good at sharing with their friends. But a sense of justice also requires the ability to identify wrongdoers and punish them accordingly, so actually maybe that point is to religion's credit. And while I'm an atheist myself, it's hard to believe that people would have become and stayed so widely religious for so long without it having any benefits for the individual. So, with my first kid on the way, I'll be watching with interest as more evidence rolls in on this matter.