Talk of the Nation

If the Greek economy collapses, economists fear it could lead to a chain reaction that engulfs Spain, Portugal, Italy and other EU countries with fragile economies. While some experts argue doomsday scenarios are overblown, others believe the consequences would be chaotic and far-reaching.

The Census Bureau announced that for the first time non-whites now make up the majority of births in the U.S. The demographic shift raises questions about how this trend will affect policy in the country, particularly with regard to education and social programs.

Facebook hopes to raise more than $100 billion in its initial public stock offering. In a piece at Slate.com, tech columnist Farhad Manjoo warns that Facebook users can expect to see changes, including lots more ads. But he warns the company must balance profit seeking with the desires of users.

Donna Summer, who sang some of the most memorable anthems of the disco era from "Love to Love You Baby" to "Bad Girls," has died after a long battle with cancer. She had a top 40 hit every year from 1976 to 1984, including the song she once told NPR she'd perform till the very end, "Last Dance."

Truvada is a pill that's already used to treat people with HIV. A daily dose can also significantly reduce the risk of new infection. And a panel recommended the FDA approve an over-the-counter HIV test, OraQuick. Users could test and interpret their results at home in as little as 20 minutes.