It came as a huge and unpleasant shock to Steve (Stephen Nichols, near r.) to learn in 1987 that Jack (Matthew Ashford) was his brother, given up for adoption by their mother, Jo.
Lucas’s (Bryan R. Dattilo, l.) world was rocked in 1994 when it was confirmed that he and Austin (Austin Peck, pictured in 2006) share the same mother, Kate.
Philip (then-Kyle Brandt, near r.) and Rex (Eric Winter) had big news to absorb in 2003: They are half brothers, both the biological sons of Kate.
In 2005, Shawn (then- Jason Cook) and Chelsea (Rachel Melvin) proved to be half siblings who have the same father, Bo.
Chad (then-Casey Jon Deidrick, r.) found out in 2010 that Stefano is his birth father, making EJ (James Scott) and Lexie (Renee Jones) his half siblings.
In 2015, Theo (Kyler Pettis) found out about the existence of his half sister, Lani (Sal Stowers), who was also fathered by Abe.
Brady (Eric Martsolf, l.) got a bonus half brother in 2015: Paul (Sean Christopher), who is also the son of John.
Joey (James Lastovic, l.) and Tripp (Lucas Adams) discovered in 2017 that they are half brothers, with Steve as their common father.