HOW TO REPLY A MUSLIM
Muslims take their morality from their allah(Muhammad alter ego) and the first question they ask an atheist is why they dont have sex with their mother.
ANSWER; We are genetically enshrined for survival . All humans have genes againts admiring close relatives. The goal is to enhance species survival and reducing introduction of lethal genes and abnormal genes into the population. BUT MUSLIMS take their morality from their allah and Muhammad..that means they dont have sex with their mother only because allah said they should not do else they will have done it.
A typical example is Muhammad's marriage to his cousin which became a moral example to follow and now children are born with defects and brain disorders. In effect, atheist are morally superior to Muslims because they dont need a book to tell them about morality, something Muslims cant do without..