Weiner: Seven U.S. women who made a difference in 2013

Whether it was by showing courage when confronting a personal tragedy, by reminding us of the collective tragedies Americans have faced over the decades or merely by proving that there's no stopping women from reaching the top, throughout 2013 these U.S. women made us think about what is important in our own lives.

• Myrlie Evers-Williams, for keeping America's focus on the work that still needs to be done to advance civil rights. The year began on a joyful note when Evers-Williams delivered the invocation for President Barack Obama's second inauguration, making the 80-year-old activist the first woman to lead the prayer at the ceremony. Evers-Williams' speech set the tone for a year of tragic and triumphant remembrances, from the 50th anniversary of the assassinations of her husband, NAACP leader Medgar Evers, and of President John Kennedy, to the 50th anniversary of the March on Washington, led by civil rights champion Rev. Martin Luther King Jr., and the 150th anniversary of President Abraham Lincoln's Emancipation Proclamation.

• Gabrielle Giffords, for pressuring Americans to do something about the thousands of innocent people who die each year because someone shot them with a gun. On Jan. 30, Giffords, a former U.S. representative from Arizona, got all of America's attention when she told Congress that "Too many children are dying. Too many children." The 43-year-old Giffords spoke just weeks after a young man who was barely out of his teenage years shot and killed 20 children at Sandy Hook elementary school, and two years after she had been shot in the head while holding a town-hall meeting outside a Safeway in Tucson. She and her husband, former astronaut Mark Kelly, co-founded Americans for Responsible Solutions to try and reduce gun violence.

• Robin Roberts, for not allowing cancer to derail her career and making it easier for others to face their own health issues. On February 20, Roberts returned to her desk at ABC's "Good Morning America" following a successful bone marrow transplant. Roberts had already battled breast cancer in 2007. Roberts, age 53, allowed the public to follow her treatment through video updates on "GMA" and her own diaries. On Sunday, in a Facebook posting celebrating her continued recovery, Roberts said she was "grateful" for her family and friends and "my long time girlfriend Amber [Laign]," publicly acknowledging that she is a lesbian. This statement brings a fitting capstone to a year when the Supreme Court struck down the Defense of Marriage Act as unconstitutional, ruling in favor of Edith Windsor as she sought to obtain the benefits as the widow of her spouse, Thea Speyer, that she would have been entitled to had she been married to a man.

• Sheryl Sandberg, for creating a movement that encourages women to believe that they deserve a place at the table - even if they sometimes have to excuse themselves to drive their kids to soccer practice. In March, Sandberg, Facebook's 44-year-old chief operating officer, published a manifesto titled "Lean In" (co-written with Nell Scovell) that argued that women need to change the way they perceive their place in the working world. Her book led thousands of women to launch "lean in" groups where they challenge one another to negotiate for what they deserve, to not give up their careers just because they wish to have a family, and to seize leadership roles because they have earned them.

• Janet Yellen, for proving that the best-qualified person for the job is often a woman. For much of last summer, Washington's Fed watchers argued about whether Yellen, a Fed vice chair, or Harvard professor Larry Summers would be the best person to succeed Ben Bernanke as chair of the Federal Reserve. In many ways the debate was a distraction, as there was never any doubt that Yellen has the qualifications to head the most powerful central bank in the world. She's been a member of the Fed's Board of Governors, chairman of the Council of Economic Advisers, and president of the San Francisco Federal Reserve Bank. It's hard to think of a better "apprenticeship" to lead the Fed than the one that the 63-year-old Yellen has completed. If confirmed, Yellen, who has a reputation as a fighter against high unemployment, would become the first woman to lead America's 100-year-old central bank.

• Kathleen Sebelius, for her ferocious defense of Obama's signature legislative achievement. On Oct. 1, Americans were supposed to be able to purchase health insurance online through HealthCare.gov, but computer glitches caused the site to crash, thus allowing just a handful of people to sign up for insurance that day. Two months later, the site is functioning much better and the Obama administration announced Sunday that more than 1.1 million people have chosen an insurance plan. Sebelius, secretary of Health and Human Services, has staunchly defended the Affordable Care Act and refused calls to resign following the flawed website rollout. Whether it's been through not penalizing people who don't have insurance by Jan. 1 or by allowing insurance companies to offer plans that don't meet the health law's standards, Sebelius, 65, has shown a flexibility to change the law - one that critics often refer to as "Obamacare" - when such change is needed to ensure its survival.

• Mary Barra, for breaking another glass ceiling in the corporate world. More than 100 years after the first car rolled out of its factory, General Motors has put a woman in the driver's seat and made the automotive industry another place where women have risen to the top. Barra, 52, who holds engineering and business degrees, is a career GM executive, with stints in human resources and product development. When she becomes CEO in January, Barra will bring to 22 the number of women who lead Fortune 500 companies, including Meg Whitman of Hewlett-Packard, Virginia Rometty of IBM, Ursula Burns of Xerox, Indra Nooyi of PepsiCo. and Marissa Mayer of Yahoo!

Joann Weiner teaches economics at George Washington University and contributes to The Washington Post's She The People blog. She has worked as an economist at the U.S. Treasury Department.