Well, I don't know how his Mom lost this argument, but when little Darth was born 39 years ago, his Dad was such a fan of the movie and character, he wanted to honor it by naming his son. Somehow that happened, and this 39 year old is working as a medical tech in Tennessee and has kept his name.
Meet him HERE:
http://abcnews.go.com/Entertainment/meet-real-life-darth-vader-lives-tennessee/story?id=47178064