Data from the Twins Early Development Study shows areas in the U.K. where the effect of environmental factors, shown in pink, trumps the influence of genes, shown in blue, and vice versa. TEDS hide caption

itoggle caption TEDS

First Lady Michelle Obama gardens in Soweto township, in Johannesburg, South Africa. The first lady has planted a garden on the South Lawn of the White House — it's the first vegetable garden to be planted there since Eleanor Roosevelt's victory garden. Charles Dharapak/AFP/Getty Images hide caption

itoggle caption Charles Dharapak/AFP/Getty Images

A nurse in Washington administers the whooping cough vaccine to a child in May. In response to the epidemic, more than 82,000 adults have also received the vaccine this year. Ted S. Warren/AP hide caption

itoggle caption Ted S. Warren/AP

Contact with animals and dirty environments may be one reason farm kids are less likely to get allergies, researchers say. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Isabel Doran, 4, gets a CT scan at Children's National Medical Center with her mom, Veronica Doran. The X-ray radiation in CT scans raises the risks for cancer, including leukemia, a new study shows. Dayna Smith/The Washington Post/Getty Images hide caption

itoggle caption Dayna Smith/The Washington Post/Getty Images

New Haven Public Schools' summer food truck will deliver an expected 40,000 free meals to kids in eligible neighborhoods during July and August. Timothy Cipriano/New Haven Public Schools hide caption

itoggle caption Timothy Cipriano/New Haven Public Schools