On Strong Medicine, Tamera Mowry joined the cast at the beginning of the fifth season as Dr. Kayla Thorton. Her character is depicted as a young prodigy who quickly rises up from her residency to become a go-to ER doc. In the clinic, she often deals with difficult patients who don't take her seriously as a doctor, but arguably her most difficult patient was one of Kayla's last ones.
In the sixth season episode "My Sister, My Doctor, Myself," Kayla gets a rather surprising visit to the women's clinic. It's her estranged twin sister Keisha, portrayed, of course, by Tamera's actual twin sister Tia Mowry. The pair memorably starred in an ABC sitcom in the 1990s called Sister, Sister, which originally aired as part of the network's popular TGIF lineup of family sitcoms. That makes this episode a double surprise for any fans of 1990s TV who happened to catch this onscreen family reunion of the TGIF alums on Strong Medicine.
For Dr. Kayla Thorton, family plays a key role in the nature of her character, but initially that has nothing to do with her twin sister. We don't even know she exists. Instead, we learn on the show that Kayla's motivation to become a doctor sprang from a traumatic moment when she was a young girl. She watched her brother get shot, then die in her arms, with the closest doctor too far away to be even worth a call.
These community issues were a central theme on Strong Medicine, questioning which patients got access to care when, but while Kayla's big heart frequently sees her to go any lengths to cure what ails her patients, when it came to her twin sister, the medical issue that arises couldn't be further from Kayla's purview.
It's revealed in "My Sister, My Doctor, Myself," that Kayla's twin sister has bipolar disorder, ultimately requiring 24-hour care. In the end, Tia takes a deep breath and tells her sister both onscreen and off, "This is my problem. I have to own it." As Tamera's Kayla tears up, she tells her twin she feels like she's sending her to Death Row. Tia's Keisha says, "If you didn't have the connections to get me in here, and left me on my own, it would be like you sent me to Death Row." Kayla promises to visit. A lot. It's a much more serious side to the "sibling syncronicity" the Sister, Sister theme song sang about.
Curiously enough, one of the first episodes to feature Dr. Kayla Thorton also focused on a pair of estranged sisters. In the fifth season episode "Life in the Balance," Olympic gymnast Kerri Strug guest stars as a world champion gymnast who finds out her estranged sister is in desperate need of a liver transplant. It's another strong story on sisterhood, which is definitely within Strong Medicine's wheelhouse, and perhaps the best way to up the ante and prod that story further was to tumble from distant sisters to alienated twins for the show's final season.