if Captain Jack Harkness (John Barrowman's character) estola 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 tu hear his father say Jack Harkness get over here now! He dicho it was a convenient maybe that's part of it.

In episode "Adam" The image that he had of his past was created por 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. o maybe Jack's parents named him Captain Jack Harkness after the actule Captain Jack Harkness. Just a thought.