Virgin birth of Jesus
Raymond Brown argues that Jesus may have been an illegitimate child.  This idea first appeared around 177-180 AD.  Around this time, Celsus wrote that Jesus himself had made up the story about being born to a virgin.  In fact, Celsus wrote, Jesus' mother was a poor country woman who earned her money by spinning (making thread). She had been married to a carpenter, but he kicked her out.  He did this because she was convicted of adultery with a soldier named Panthera.  After this, she wandered around and secretly gave birth to Jesus.  Later, because he was poor, Jesus found work in Egypt.  There, he learned magical powers.  These made him confident, and he started calling himself God.