There's a widely held assumption that a slight imbalance in male births has its start at the very moment of conception. But researchers say factors later in pregnancy are more likely to explain the phenomenon. CNRI/Science Source hide caption

itoggle caption CNRI/Science Source

At Resource Management's Materials Recovery Facility, workers pull plastic bags, other trash and large pieces of cardboard off the conveyor belts before the mixed, single-stream recyclables enter the sorting machines. Véronique LaCapra/St. Louis Public Radio hide caption

itoggle caption Véronique LaCapra/St. Louis Public Radio

Homeowners sit in a conference room in Detroit's Cobo Center while waiting for their cases to be heard to avoid foreclosure from tax debts in Detroit on Jan. 29. This year, Wayne County officials sent out 62,000 foreclosure notices to city homeowners behind on property taxes. Paul Sancya/AP hide caption

itoggle caption Paul Sancya/AP

Cholita, an Andean bear, was abused in a circus in Peru and is now in a small zoo. An animal welfare group has now received permission to take Cholita to a wildlife sanctuary in Colorado, along with more than 30 former circus lions. Courtesy of Animal Defenders International hide caption

itoggle caption Courtesy of Animal Defenders International

Pakistani activists march in support of the Saudi government at a protest in Quetta on March 30, 2015. Pakistan is the latest country to join a Saudi-led coalition fighting Houthi rebels in Yemen. BANARAS KHAN/AFP/Getty Images hide caption

itoggle caption BANARAS KHAN/AFP/Getty Images

Would-be presidential candidates are ditching "testing the waters" and "exploratory committees" to hold onto unlimited and undisclosed cash for longer. Mark Wilson/Getty Images hide caption

itoggle caption Mark Wilson/Getty Images

Sen. Elizabeth Warren talked about 2016 to WBUR's Here & Now: "What I care about is that everyone who runs for president, who runs for any national office right now, talks about this core set of issues." Manuel Balce Ceneta/AP hide caption

itoggle caption Manuel Balce Ceneta/AP

A little booze can't hurt: The Hy-Vee grocery chain has added a Market Grille to several of its locations in the Midwest and Great Plains. You can order drinks and dinner before or after you do your grocery shopping. Courtesy of Hy-Vee Market Grille hide caption

itoggle caption Courtesy of Hy-Vee Market Grille

In this March 5, 2015 file courtroom sketch, Dzhokhar Tsarnaev, center, is depicted between defense attorneys Miriam Conrad, left, and Judy Clarke, right, during his federal death penalty trial in Boston. Jane Flavell Collins/AP hide caption

itoggle caption Jane Flavell Collins/AP

An FDA field inspector in Los Angeles checks imported shrimp, February 2009. More than a dozen federal agencies play a part in keeping food from making Americans sick. Critics say that leads to a lack of coordination, a patchwork of rules and holes in the system. FDA hide caption

itoggle caption FDA

In The Shame In Venice 2, Kenyan artist Michael Soi protests the makeup of his country's pavilion at the Biennale. Courtesy of Michael Soi hide caption

itoggle caption Courtesy of Michael Soi

After a car attempted to crash a gate outside the NSA Monday morning, Maryland state police blocked the freeway entrance that accesses the agency's headquarters in Fort Meade, Md. Patrick Semansky/AP hide caption

itoggle caption Patrick Semansky/AP

Indiana Senate President Pro Tem David Long (left) and House Speaker Brian C. Bosma, both Republicans, discuss their plans for clarifying the Indiana Religious Freedom Restoration Act during a news conference today at the Statehouse in Indianapolis. Michael Conroy/AP hide caption

itoggle caption Michael Conroy/AP

Airplanes' contrails streak the sky close to where a Germanwings plane crashed last week, in Seyne les Alpes, France. Thomas Lohnes/Getty Images hide caption

itoggle caption Thomas Lohnes/Getty Images