Ginsburg, who spoke Friday to an assembly at Suffolk Law School, said she sees more women in law school, arguing before her court and sitting as federal judges. But there is not enough female perspective on the nine-member high court, she said.
"We have very different backgrounds," Ginsburg said of herself and O'Connor. "We divide on a lot of important questions, but we have had the experience of growing up women and we have certain sensitivities that our male colleagues lack."
Ginsburg, 73, did not take questions afterward to elaborate.
"It was good for the public to see that women come in all sizes and shapes, just as men do, and they don't necessarily look alike or think alike," she said.
O'Connor, a moderate who retired from the high court last January, became its first female justice when President Ronald Reagan appointed her in 1981.
Ginsburg was appointed by President Bill Clinton in 1993 and is among the court's liberal wing.
President Bush nominated White House counsel Harriet Miers in October 2005 to replace O'Connor, but Miers dropped out under fire from conservatives who questioned her qualifications. Mr. Bush then turned to Samuel Alito, a federal appeals court judge from New Jersey, who was ultimately confirmed.
Ginsburg, who in the early 1970s successfully argued gender-discrimination cases before the Supreme Court, said she is encouraged by the numbers of female judges on lower courts.
"My consolation is that if you look at the federal courts altogether, you get a much different picture than you do if you look only at the U.S. Supreme Court," she said.
Renee Landers, who teaches constitutional law at Suffolk and attended the speech, identified with Ginsburg's comments. "We've all had the experience, alas even now, of being the only woman in the room," she said.