National and World News from NPR

Last May, German investigators found secret files embedded in a pornographic video on memory cards being carried by a suspected al Qaeda operative. Peter Wayner describes the history and technology of the technique for hiding information, known as steganography.

Gay marriage gets an advocate in the White House, but only after Vice President Joe Biden has his say. President Obama's announcement comes a day after North Carolina voters overwhelmingly rejected the concept. And Dick Lugar's 36-year Senate career comes to an end in Indiana. Meanwhile, in the West Virginia primary, Obama defeats a jailed felon from Texas, 59 percent to 41 percent.

Listen to the latest political roundup with NPR's Ken Rudin and Ron Elving.

A group of science advocates say the American president should have the basic scientific know-how to understand policy challenges, evaluate options and devise solutions. Ira Flatow and guests discuss how a presidential science debate can help voters decide if a candidate is up for the job.

A new study shows eligible voters who favored whites over blacks- either consciously or unconsciously- also favored Republican candidates relative to Barack Obama. Psychologist Anthony Greenwald discusses the results and why racial attitudes continue to predict voter preference in 2012.

The U.S. Conference of Catholic Bishops sent an "official inquiry" to the Girl Scouts of the USA. NPR's Barbara Bradley Hagerty reports the bishops will investigate whether the iconic group has ties or views that conflict with Catholic teaching.

Barbara filed this report for our Newscast unit:

A new four-part documentary airing on HBO next week looks at America's growing weight problem. John Hoffman, vice president of HBO Documentary Films and executive producer of The Weight Of The Nation, describes his three year-project to document the causes and effects of being overweight and obese in America.

When members of a travel soccer team in Oregon fell ill last year, the details of how the disease spread through the team were mysterious. Kimberly Repp, an epidemiologist in Washington County, Oregon, describes the medical detective work that led epidemiologists through the chain of transmission of the norovirus.

The Garbage-Men is a band of high school-aged musicians who play instruments made out of recycled cereal boxes, buckets, and other materials they've rescued from the trash. Guitarist Jack Berry and drummer Ollie Gray talk about the band and their signature "trashy" sound.