A: The short answer is no. But of course, when it comes to religion and morality, short answers rarely suffice.
The longer answer to this question is "it depends". Specifically, it depends on how you define "moral", because it's very easy to define someone right out of the picture. Many theists, for example, flatly believe that morality and religion are essentially the same thing. Under that definition, it is literally impossible for a non-believer to be moral.
You quickly see the difficulties inherent in discussing what is and is not moral when you start getting into hot-button American moral political issues like abortion, pornography, and homosexual rights. Each camp defines their position to the moral one, and the other camp's to be immoral. If you think homosexuality is inherently immoral, then by definition all gay people are immoral. If you think tolerance (at a minimum) of homosexuality is moral, then theists who condemn homosexuals are inherently immoral.
In other words, it's all in how you define it.
One common approach to answering the question of whether atheists or theists are more moral is to pick an issue and see how each group fares with regards to it. While this approach can be very useful, it is also easily abused. For example, many Christians like to point to a Barna Group survey that shows atheists are about half as likely as Christians to give to charities. Since charity is commonly considered a great moral good, the Christian thus "proves" that atheists are less moral.
On the other hand, Barna also found that atheists are about half as likely as Christians to get divorced. Most Christians consider divorce to be a great moral failing, so by using this example, atheists "prove" they are more moral than religious people. You can see why it's so important to treat these kinds of surveys cautiously, and not to overgeneralize from them. Morality and human behavior are very large, very complex subjects with lots of moving parts. Cherry-picking one example from the bunch and trying to hold it up as definitive is misleading.
But I think what most people mean when they talk about morality pretty much involves adherence to the Golden Rule: "Do unto others as you would have them do unto you". Honesty, kindness, a giving nature, bravery, helpfulness, faithfulness to your word, being respectful of others, dependability, and so on; in other words, how we treat others.
And that's where much of the Christian angst over atheism's supposed lack of morality, I suspect, comes from. There is a fear that atheists, without hanging their moral code on a religious tradition, will have no reason to adhere to the Golden Rule, causing the social order to collapse, leaving us all in a bleak, grim, Hobbesian struggle for survival as savages, where might makes right and the strong prey on the weak with no conscience at all. To that concern, all I can say is, look at Norway:
Depending on the definition of atheism, Norway thus has between 26 percent and 71 percent atheists. The Norwegian Humanist Association is the world's largest humanist association per capita.
And what has secularism done to Norway? The Global Peace Index rates Norway the most peaceful country in the world. The Human Development Index, a comparative measure of life expectancy, literacy, education and standard of living, has ranked Norway No. 1 every year for the last five years.
Norway has the second highest GDP per capita in the world, an unemployment rate below 2 percent, and average hourly wages among the world's highest.
