Catelynn Lowell and Tyler Baltierra are among the most recognizable faces from MTV’s Teen Mom franchise, largely because of their uniquely emotional story.

Unlike many of their castmates, their journey has centered not only on young parenthood, but also on adoption, long‑term mental health struggles, and a relationship that has been tested in the public eye for more than a decade.

Are they siblings?!

Catelynn and Tyler Baltierra from Teen Mom are not biological siblings. They were temporary step-siblings from 2009 to 2013, when their parents (April and Butch) were married.

However, they were already a couple before that marriage and have remained together since, never sharing a biological parent.