The Parker family was a family of Hill Valley.
It began with a line of Parkers in the late 19th Century and later Mr. Parker and his daughter Jennifer Parker.
Family tree
Danny Parker---------+--------Betty Parker | | Mr. Parker | | Jennifer Parker
Behind the scenes
According to Robert Zemeckis, Jennifer Parker was named after Los Angeles attorney Larry H. Parker, who had defended Zemeckis on a copyright infringement lawsuit.