First, a brief study in any period of human history gives hard evidence that a belief in God does not promote morality and goodness. The most horrific evils perpetrated by man use religion as an excuse. Witch burnings, the Crusades, civil wars, the Holocaust, 9/11; people killing each other over who has the better imaginary friend.
If a belief in God is the only thing making us good, that belief is failing. Personally, I think we need to be responsible for creating meaning in our own lives. The pursuit of meaning leads us to love, generosity, creativity and intellectual discovery. It is too depressing to think that we need a “Bogeyman” or someone who will dole out eternal rewards and punishment to frighten us into good behavior. Next, you have to admit that we are all “atheists”. It is simply a matter of which god/s and goddess/es you donnot believe in. Do you believe in Zeus, Coatlique, Baal, Vishnu? No? Then you are an atheist. The god you believe in is an accident of birth.
If you believe that God planned your birth so you would be placed on a path to follow the teachings of Jesus Christ instead of Mohammed, does it follow that you are one of His chosen? I think your Muslim brothers may take offense. Or perhaps it is the other way round and you consider yourself more blessed, more loved by God, than your Christian friends. This is how conflicts begin. In regard to the shortcomings of science: of course there are mysteries that we have yet to unravel, many phenomena cannot yet be explained through science. Before the invention of the microscope, it was widely believed that evil spirits caused illness. Before telescopes and mathematics, it was believed that the Earth was the center of the universe. Many were martyred by the Church for speaking scientific truth.
The reality of our existence is so much richer and elegant than any supernatural creation myth could ever be. Consider what a rare and precious thing life is. And of course, it did not “just happen.” Life on Earth is the result of over 4 billion years of experimentation, of trial and error, by nature. Only human beings could be as arrogant and narcissistic as to believe that the Universe was created for them.