if Captain Jack Harkness (John Barrowman's character) चुरा लिया the name and isn't actually called Captain Jack Harkness, then how come, in the flashbacks in the episode of Torchwood 'Adam', his parents call him Jack? :L

Because his real name might be Jack and he added in Harkness on earth. Did आप hear his father say Jack Harkness get over here now! He कहा it was a convenient maybe that's part of it.

In episode "Adam" The image that he had of his past was created द्वारा Adam. Who in fact does NOT know his real name just like the other Torchwood members. So, his parents might have called him a different name. But because nobody knows Jack's real name Adam cant recreate the memory perfectly. या maybe Jack's parents named him Captain Jack Harkness after the actule Captain Jack Harkness. Just a thought.