Sen. John Kerry (D-Mass) looks on as President Obama announces his nomination to be secretary of state on Dec. 21. (KEVIN LAMARQUE/REUTERS)

President Obama brought his top Pentagon and Central Intelligence Agency chiefs together Monday with their potential replacements, and some critics noticed one thing that stood out: Each of them was a white man.

Obama, who made women’s issues a core of his reelection bid, has nominated men to serve in three of his most prominent national security positions, including secretary of state, where Sen. John F. Kerry (D) was named last month to replace Hillary Rodham Clinton. The president on Monday announced former senator Chuck Hagel for the defense job and counterterrorism adviser John O. Brennan to head the CIA.

The moves have disappointed some supporters who said they fear, with Clinton’s departure, a paucity of females among Obama’s top advisers, particularly in the traditionally male-dominated field of defense and security.

Thomas Donilon, the president’s national security adviser, was in the audience, as outgoing Defense Secretary Leon E. Panetta and acting CIA director Michael J. Morrell joined their possible successors and the president.

The pattern is particularly striking for a president who was elected with majority support from women and racial minorities and focused heavily during his reelection campaign on women’s health concerns and equal pay in the workplace. Obama won 55 percent of the female vote to Republican rival Mitt Romney’s 44 percent.

Obama is committed to “finding the very best people for each job,” White House press secretary Jay Carney said Monday, when asked about the lack of women among the second-term appointments. “And that’s what he’s done today, and that’s what he’ll continue to do.”

Among those passed over to lead the Pentagon was Michele Flournoy, who became the highest-ranking woman to serve in the Defense Department when she was confirmed as undersecretary of defense for policy in 2009. Flournoy, 52, resigned from the role last February, citing a desire to spend more time with her family. But she also served as an adviser to Obama’s reelection campaign and was considered a top candidate.

Instead, Obama chose Hagel — who got to know Obama when he was a senator — though the Nebraska Republican has been criticized by GOP leaders and some Democrats for statements on Israel.

“I think he’s blowing a huge opportunity here for reasons I don’t even get,” said Rosa Brooks, a professor on national security at Georgetown University who spent two years working for Flournoy at the Pentagon.

“It would have been fantastic for this president to appoint the first woman secretary of defense,” Brooks said, “particularly given we are so embroiled at this moment in the ongoing conflict in the Islamic world, where the suppression of women is such a major issue. It was a chance for us to show we’re leading by example.”

Carney noted that Janet Napolitano, head of the Department of Homeland Security, and U.N. Ambassador Susan E. Rice are in top national security roles.

He added that Obama “insists on diversity on the lists that he considers for the job because he believes that in casting a broader net, you increase the excellence of the pool of potential nominees for these positions. But in the end he’ll make the choice that he believes is best for the United States.”

Those choices are likely to continue over the next week or two with the highly anticipated announcement of a replacement for outgoing Treasury Secretary Timothy F.Geithner. The leading candidate for the job is reportedly White House chief of staff Jacob J. Lew; Lael Brainard, Treasury undersecretary for international affairs, has also been mentioned.

Lew, in turn, could be replaced by deputy national security adviser Denis McDonough or Ronald A. Klain, a former aide to Vice President Biden. With Attorney General Eric J. Holder Jr., an African American, likely to remain in place, that could leave as few as three women among 15 official Cabinet posts, though several others serve in Cabinet-rank positions, such as U.N. ambassador.

Paul C. Light, a professor at New York University who studies presidential appointments, said Obama is likely to have a less diverse Cabinet in his second term than his first, and it could be even less diverse than George W. Bush’s Cabinet. Terry O’Neill, head of the National Organization for Women, said she was “disappointed so far” by the president’s selections.

During the campaign, Obama made women’s issues on health and equal pay a core tenet of his reelection message. Many Democrats mocked Romney when he said during a debate that he had asked for “binders full of women” when he was trying to fill top jobs while serving as governor of Massachusetts.

Obama picked up on the line during his stump speeches, telling one audience that “when the next president and Congress could tip the balance of the highest court in the land in a way that turns back the clock for women and families for decades to come, you don’t want someone to ask for binders of women.”

But the president has also been criticized for having relatively few women among his insular group of trusted advisers, and critics continue to note that Obama plays golf — one of his favorite recreational activities — and basketball almost exclusively with male friends.

Inside the White House, Valerie Jarrett remains one of his closest advisers, but a book published in 2011 reported that friction over the roles of women was so strong at one point that Obama took steps to reassure his female staff.

Marcia Greenberger, co-president of the National Women’s Law Center, praised Obama’s record on diversity and said she will reserve judgement on his second-term Cabinet. Greenberger said that the “general principle is that it’s always an occasion for celebration” when women “break those ceilings” in traditionally male fields.

“I think it’s a stronger team when there is diversity and women’s perspectives and expertise are represented,” Greenberger said. “We don’t know the full picture yet.”

Emily Heil contributed to this report.