She is of English, and some Scottish, descent. Some of her ancestors were American-born, with several family lines leading back to New England of the 1600s.
After living in the US for 34 years, she became a US citizen in August of 2005 so she could vote against US President George W. Bush as part of her protest against the war in Iraq.
In the Banacek episode "A Million the Hard Way" (1972) when Banacek (George Peppard) introduces himself she replies, "Banacek, just one name? Like Superman?" That was six years before her first appearance as Lois Lane.
Best known as Superman's favorite person, Lois Lane. Her much publicized behavior in 1996 was due to manic depression. She was living in a state of paranoia, convinced that her first husband was trying to kill her. Kidder soon lived as one of the homeless. She narrowly escaped being raped, and wandered about the streets of Los Angeles (barely recognizable after cutting her hair off and removing some of her dental work) before hiding underneath a family's porch that was located near the studio where Superman (1978) was filmed. Fortunately, her life is back on track after having faced the "demons" of her condition.
On Aug 25, 2002, she suffered a broken pelvis near Belfast, Maine, when her GMC Yukon hit a raised pavement and rolled over several times. She had just come from hosting the 15-Minute Festival, a series of original plays staged at the National Theatre Workshop of the Handicapped. She was on her way to Montreal at the time of the accident. Kidder's friend, David Stuckey, said that the actress won't require surgery but will remain for several days at Waldo County General Hospital in Belfast. Stuckey said Kidder was in a lot of pain. "But she's in good spirits," he said. "She's OK."