These are all the members on the show (excluding adults) that are orphans. They include members from the X-Men, The Brotherhood, and The Acolytes. An Orphan is an individual who has neither a mother or a father. Children with at least one living parent are not orphans. Children who were abandoned are not orphans.
Scott Summers
Orphaned at age 7
Alex Summers
Orphaned at age 4
Rogue
Orphaned at age 4
It is unknown if Rogue was given up for adoption, and then adopted in the same year, or had lived at an orphanage for the first 4 years of her life.
Remy Lebeau
Orphaned after birth.
Lance Alvers
Orphaned after birth.
Kurt Wanger
Abandoned by his mother at birth, raised believing he was an orphan
Rahne Sinclair
Raised to believe she was Orphaned at birth.
Her mother died at birth and was raised by her father Reverend Craig who made her believe she was an orphan.