OKLAHOMA - The story is a head-shaker.
An Oklahoma mother arrested and charged with incest for marrying her own biological daughter.
Patricia Spann, 43, and her biological daughter Misty Spann, 25, are behind bars, charged with incest for getting married.
"I think she's worthless," said Patricia's son Cody Spann. "She put my sister into this. She forced my sister into this. Now, you got my sister behind bars facing time in prison because of your choices. Let that sit on you as a mom."
Cody seems to characterize the relationship as his mother's abuse of his sister.
Meanwhile, the internet has exploded with theories about the taboo relationship.
Some call it a case of 'genetic sexual attraction.'
"All the evidence would show this is not very common at all," said UCO Associate Professor Dr. Caleb Lack.
GSA is most often a factor when the couple does not know they are related.
"One thing we see in research is that people in general are physically attracted to other people who look similar to them physically," said Lack on why the term GSA is now being used to describe the Spann case.
"It's pretty bizarre, and it's pretty far out there and it's very unusual," said Psychologist Dr. Stewart Beasley.
Beasley believes part of the reason the case is so shocking and disturbing is because incest usually involves a parent and a minor child, not two adults or, in this case, three adults, as the mom is alleged to have also married her oldest son years ago.
"We typically think of that as a parent and a young child or an adolescent. And, this goes outside that and was complicated two or three times," Beasley said.
No criminal charges have been filed for the allegation of marrying the older brother.