Not everybody is who they say they are, and as the people in this gallery found out, that applies to family members too. From secret half-siblings to affairs to straight-up swingers, these 22 folks shared the biggest secrets they discovered about their family. 

After the death of one man's parents, he decided to clean out their old house and put it up for sale. With some help from his sister, he stumbled across some old tapes in the attic. After watching one, they knew they were in for a big surprise. It didn't take many tapes to learn that their parents had been swingers with the parents of other very close childhood friends. Having seen more than enough they both elected to stop watching the tapes then and there, but with hundreds more, who knows what they might have found?

Another child learned on her 21st birthday that she had a secret older sister who had died in infancy, who she never knew about seeing as the parents had decided to carry on and pretend that she was actually just the first child. The result meant struggles academically and socially as she tried to fit in with kids who were actually two years older. Now that's a strange secret to learn.