I'm an atheist and I don't necessarily disagree with this conclusion...but the way it's presented makes me question the veracity of these claims.
First of all, no distinction appears to be drawn between correlation and causation. The study is correct in noting that the United States is more religious than other developed nations, and it is correct in noting that the United States generally has more problems related to sexuality, crime, abortion, etc.
But from that information, can you really draw the conclusion that religion CAUSED those problems? I think not. Could they be correlated without there being a causal relationship? Absolutely. Could a few of those statistics simply be a coincidence? Absolutely; the number of developed countries in the world is hardly a large statistical sample.
Let's examine the problems in the United States that this study claims are caused by religion:
1. Violent crime / murder / suicide - Are these really caused by religiosity? Or do they have to do more with the fact that the United States has greater wealth disparity and poorer education than most other developed nations? Whether or not you agree with American economic policies, I think it's fair to conclude that more relatively poor and uneducated people means more crime.
2. Abortion - The abortion rate is greater in the United States than in most other developed countries...but that's partly because abortion is illegal in most other developed countries. Once again, whether or not you agree with abortion, I think it's fair to conclude that when a country makes it illegal, it lowers the rate at least somewhat.
3. Sexual promiscuity - I have to agree that religion probably does play a role with this one, or at least America's brand of religion. Societies where sex is a relatively open-for-discussion topic tend to have lower rates of sexual promiscuity and lower rates of STDs. Societies (like the United States) where people are more conservative tend to have higher rates because people have less access to good health information regarding sex. This kind of conservatism usually (but not always) coincides with religiosity, so I think a causal relationship may exist in this case.
Also, I'd like to clear up a couple errors in this study. According to the study and/or the article:
“The United States is almost always the most dysfunctional of the developing democracies, sometimes spectacularly so.” - This is arrogant and simply not true. Our social ills are different from those of other countries, but aren't necessarily greater overall. Should we conclude that religiosity promotes a strong economy, since the economies of the America/Ireland/Poland are among the strongest of all developed nations? I think not. Correlation or coincidence does not imply causation.
"He said that most Western nations would become more religious only if the theory of evolution could be overturned and the existence of God scientifically proven. Likewise, the theory of evolution would not enjoy majority support in the US unless there was a marked decline in religious belief, Mr Paul said." - I don't think this is necessarily true. Over the decades, Americans have become more accepting of evolution, even though their religiosity has remained about the same. It is fair for the study to say that the large number of people who don't believe in evolution in the United States CAN be attributed to religion...but even among religious people, those with a higher education are much more accepting of evolution.