Grey's Anatomy showrunner Krista Vernoff teases that viewers may find out which of Derek's sisters Lucas' mother is during the upcoming season 20.

Warning: SPOILERS ahead for Grey's Anatomy season 19, episode 12.Grey's Anatomy showrunner Krista Vernoff believes that season 20 of the series could reveal which of Derek's sisters Lucas' mother is. The long-running medical drama introduced surgical intern Lucas Adams in season 19, episode 1, who was revealed to be Derek Shepherd's nephew. The show has yet to reveal which of Derek's four sisters is Lucas' mother, making it a point of mystery for viewers in season 19.

Speaking with TVLine, Vernoff hinted that Grey's Anatomy season 20 may confirm which of Derek's sisters is Lucas' mother. Her explanation indicated that Lucas' parentage likely wouldn't get touched on before season 19 comes to a close in May. Check out what Vernoff had to say below:

I have no doubt that you will next season. Probably not this season.

Who Will Lucas' Mother Be In Grey's Anatomy Season 20?

With Lucas having such a strong, tangential connection to Derek, his presence in Grey's Anatomy season 19 feels important to honor the legacy of Meredith's late husband. Harboring a familial connection to one of Derek's sisters, Lucas manages to carry on the legacy of his family name, even as Ellen Pompeo reduces her involvement in the series as Meredith. This opens the door for Lucas to garner more of a focus in season 20, making it the perfect time for his parentage to be revealed.

It has already been confirmed that Lucas is Amelia's nephew, leaving Kathleen, Nancy, and Liz as possible candidates. All three have children, but the information that Lucas gives about his mother points to Nancy as the most likely candidate. In season 19, episode 3, Lucas mentions that he's from Connecticut, which is also where Nancy lives. If Nancy still resided in the state past her last appearance in season 15, then she is most likely to be revealed as Lucas' mother.

However, Grey's Anatomy has been willing to throw their storylines for a loop in the past, meaning Lucas being from Connecticut may be a misleading fact to make viewers think Nancy is his mother. It's still just as possible for Kathleen or Liz to be revealed as his mom despite the current bits of evidence indicating it is Nancy. While it could be a misleading fact, evidence indicates a high probability that Grey's Anatomy season 20 could reveal Nancy as Lucas' mother.

Source: TVLine