That focus on how many people in this world can love one specific person is very nerdy, DeGruy said.

CNN: STORY HIGHLIGHTS

And although sci-fi fans deeply identify with the characters on the show, it's the writing on "Torchwood" that keeps fans dedicated, DeGruy said.

CNN: STORY HIGHLIGHTS

"Despite the fact that Jack is 'try-sexual' -- he'll try anything -- his relationship with Ianto reached a peak in 'Children of Earth, ' " said Edward DeGruy, British sci-fi fan and senior director of guest hospitality for DragonCon, a fan convention in Atlanta.

CNN: STORY HIGHLIGHTS