Ronda Kaysen: Pro-choice groups are wringing their hands about Obama's pick for the Supreme Court. Sonia Sotomayor has never made any major rulings about Roe v. Wade, and in the few instances where she has ruled on issues relating to abortion, she's come out on the side of pro-life. Some are beginning to wonder if the woman who's poised to be the first Latina to sit on the nation's highest court is a stealth candidate.

"We simply don't know Judge Sotomayor's view on the bedrock constitutional case of Roe v. Wade," Nancy Northup, the president of the Center for Reproductive Rights, told CBS News.

In letters to supporters, pro-life groups sound anxious. "Discussion about Roe v. Wade will -- and must -- be part of this nomination process," Nancy Keenan, president of NARAL Pro-Choice America, wrote in a letter to supporters. She then urged them to press their senators to question Sotomayor about her position on abortion. "As you know, choice hangs in the balance on the Supreme Court as the last two major choice-related cases were decided by a 5-to-4 margin."

When asked if Obama vetted Sotomayor about her stance on abortion, White House spokesman Robert Gibbs said that the president "did not ask that specifically."

In 2002, Sotomayor ruled to uphold the Bush Administration's global gag rule, stating, "The Supreme Court has made clear that the government is free to favor the anti-abortion position over the pro-choice position," she wrote, "and can do so with public funds."

In 2004, she sided with anti-abortion protesters who wanted to sue the police for using excessive force to break up their demonstrations outside an abortion clinic. 

In several rulings she's made about granting amnesty to women from China who are escaping forced abortions and forced sterilizations, she has ruled in favor of the refugees. Pro-choice groups oppose forced abortions and forced sterilizations. However, some of the language Sotomayor has used in her rulings has made pro-choice activists uneasy. In a case in which other judges on the bench argued that men from China couldn't get amnesty, she wrote:

"The termination of a wanted pregnancy under a coercive population control program can only be devastating to any couple, akin, no doubt, to the killing of a child," she wrote, also taking note of "the unique biological nature of pregnancy and special reverence every civilization has accorded to child-rearing and parenthood in marriage."

Some pro-life activists are cautiously optimistic that Sotomayor, a Catholic, might support their views.

"Everyone is just assuming that because Obama appointed her, she must be a die-hard pro-choice activist," Steven Waldman, editor in chief of BeliefNet.com, a religious website, told the New York Times, "but it's really quite amazing how little we know about her views on abortion."

Yesterday, the White House moved to quell fears from the left that Sotomayor wasn't a sure vote to uphold Roe, The Hill reported. Obama, who ran on a pro-choice platform, is "very comfortable with the fact that she shares a similar interpretation to the Constitution" to the President, Gibbs said.

There have been stealth justices before. Conservatives and liberals alike assumed that David Souter, the justice Sotomayor is poised to replace, would be a reliable conservative. But he quickly turned out to be a darling of the left. In her 17 years as a judge, Sotomayor has managed to avoid laying out her ideology about issues ranging from abortion to labor rights to discrimination.

Tom Goldstein, who writes the Supreme Court blog Scotusblog, told CBS news that Sotomayor's views are largely a mystery. "There's a real air of mystery about some of the big hot button social issues that we all care about," he said.

Ronda Kaysen is a freelance writer. Her work has appeared in the New York Times, Washington Post, BusinessWeek.com, Architectural Record, Huffington Post, New York Observer and AM New York. She lives in Brooklyn with her family.