"Grey's Anatomy" fans have been wondering what Martin Henderson's character Nathan Riggs' true connection to Owen (Kevin McKidd) really is.

During the first half of the hit ABC series, only few details about the character was unveiled. According to one fan, it's possible that Nathan is a transgender and he also happens to be Owen's long-lost sister. However, in an interview with TV Line, TV journalist Michael Ausiello slammed rumore that Nathan and Owen are related to each other biologically.

"Highly unlikely. When Rhimes cast the New Zealand native, she didn't want him to 'dampen down' his accent too much, Henderson told me when we spoke last month, adding, 'She wanted the character to have an international feel.' Last I checked Owen was born and raised in Seattle, not New Zealand. The bigger mystery as I see it is whether his MIA sister is dead or alive," he said.

Meanwhile, according to Design & Trend, there have been ongoing rumors that Owen's sister may have died because of something that Nathan did. Some fans also believe that Nathan and Owen's sister were previously married to each other. If not, at least they were in a serious relationship.

In other news, "Grey's Anatomy" Season 12 will also reveal whether or not Owen and Amelia (Caterina Scorsone) will choose to continue with their relationship.

During the fall finale episode, Caterina and Meredith (Ellen Pompeo) had a bit of a falling out after Meredith refused to tell the former what Owen told her. Owen, on the other hand, is known for keeping things to himself so he also didn't bother telling Caterina what his problems were. In the past, Owen had a similar problem with his ex Cristina (Sandra Oh), and this became one of the reasons why they eventually ended their relationship.

"Grey's Anatomy" Season 12 airs Thursdays at 8 p.m. ET on ABC.