Brothers and Sisters - Season 5 - Eps 20: Father Unknown
Parenthood is questionable for more than one member of the Walker family, as Justin keeps a closely guarded secret about the true paternal identity of one of his siblings and Scotty makes a shocking discovery that will bring a new life into the Walker family fold.
About Brothers and Sisters

Title: Brothers and Sisters
First Air Date: 2006-09-24
Last Air Date: 2011-05-08
Status: Canceled
Rating: 7.1/10 (from 182 votes)
Language: EN
Seasons: 6
Total Episodes: 109
Network: ABC
Genres: Drama
Production Companies: ABC Studios, AfterPortsmouth Productions, Touchstone Television, Berlanti Productions
Synopsis
The close-knit Walker family deals with struggles and triumphs.
Cast

Dave Annable
Justin Walker

Sally Field
Nora Walker

Calista Flockhart
Kitty Walker

Rachel Griffiths
Sarah Walker

Matthew Rhys
Kevin Walker

Ron Rifkin
Saul Holden

Luke Macfarlane
Scotty Wandell

Gilles Marini
Luc Laurent

Patricia Wettig
Holly Harper