"The truth is that the court has had very few minorities and women -- ever, and right now we're dealing with 36 percent of the population is white male. You'd never know that looking at the U.S. Supreme Court or looking at the United States Congress or looking at most corporate boards," Roberts said.
Experts say there's no question that gender and life experiences play some part in judicial decisions, and women may think of things that might not occur to men.
"You may reach the same outcome, but the way you get there is different," said Phyllis Coontz of the University of Pittsburgh's School of Public and Urban Affairs. "Women are more sensitive because they think about other people."
A recent study found that on most issues there is no difference in the way that men and women draw conclusions. But then there was this: in the area of sex discrimination, female judges were found to be 10 percent more likely to rule for the victim.
"It makes sense that women would rule differently in cases where they are affected," Coontz said. "And sexual harassment is one of those instances."
The issue of gender has dominated Sotomayor's meetings with senators this week. She told them she meant her previous comments as inspirational, and if she's a justice she'll follow the law -- not her feelings.
But Republicans say they want to know more about her record and they'll scour the questionnaire.
If approved by the Senate, the 54-year-old would be the first Hispanic and third woman to sit on the Supreme Court.