Californians living in the state's agricultural regions are at risk of drinking water contaminated with harmful levels of nitrates, according to a new UC Davis report. Linked with thyroid illnesses and some cancers, nitrate contamination largely comes from chemical fertilizer and animal manure. We discuss the extent and cost of the problem, as well as potential solutions.

Going vegan can offer a range of challenges. Can you really get enough protein without meat and dairy? Can you really make eggless desserts that are anything more than a crumbly mess? Our guests say yes to both questions.

U.S. forces in Afghanistan have been warned of possible reprisal attacks following the killings of 16 civilians -- nine of them children -- allegedly by a lone U.S. serviceman. While the Obama administration says its war strategy in Afghanistan will remain intact, lack of trust on both sides complicates the future of this mission.

We hear from people struggling with mental and physical issues who are involved with a new organization called Adversity 2 Advocacy. The group focuses on turning personal challenges into service. We talk with people living with disabilities and illnesses who say that speaking out -- and advocating for education and change -- is healing.

For the first time in almost three years, California's unemployment rate fell below 11 percent in January. We look at what a slow drop in the jobless rate may mean for recovery and employment in the state.

A three-judge panel ruled Friday that a key piece of video evidence can be submitted in the domestic violence trial of San Francisco Sheriff Ross Mirkarimi. We discuss the latest developments in this legal drama that has already taken several interesting turns.

Is there one moment that changed the trajectory of your life? Or illuminated a truth? Or changed the way you think about something important? Larry Smith, founding editor of Smith Magazine, has collected stories of turning points, epiphanies and revelations from 125 writers and artists. We talk to Smith about the collection, and invite you to share the story of a moment that shifted your life.

In its first report on youth smoking in almost 20 years, the Surgeon General's Office warns that there is still a need to reduce the number of teens who smoke. Although the number of young smokers has decreased from earlier decades, the report says the rate of decline has slowed. We discuss the report's findings, and what can be done to curb youth smoking.

In 1988, former New York Times reporter Philip Taubman watched as top American and Soviet officials came close to a historic deal to eliminate all their nuclear weapons. Now, more than 25 years later with Iran's nuclear program in the news, Taubman's story of the near-abolition of nuclear weaponry still has resonance. He has written a new book about the 1980s push to "ban the bomb," and he joins us in-studio.

Cash-strapped state and local governments are increasingly looking to privatization as a way to cut costs. But opponents, such as California Assemblyman Roger Dickinson, say state workers are more dedicated and get the job done better than outside contractors. Dickinson has introduced a bill to that effect, called a "Public Employees Bill of Rights." We debate the costs and benefits of privatizing public services.

No need to turn into a Tiger Mother -- writer Pamela Druckerman says it's the French model American parents should be watching. While raising her own children in Paris, Druckerman observed a nation of hands-off, no-nonsense mothers and fathers raising well-tempered children who eat their food and sleep through the night. Should American parents raise their Jacks and Marys more like Jacques and Madelines?

Suzanne Nossel took over as executive director of Amnesty International USA in January, after a stint in the U.S. State Department working on humanitarian issues. She joins us to discuss the latest developments in Iran and Syria, and the organization's efforts to fight injustice and protect human rights around the globe.

On Saturday, talk show host Rush Limbaugh apologized for calling a Georgetown University law student Sandra Fluke a "slut" and "prostitute." A dozen advertisers have now ditched Limbaugh's show in response to the comments, which came after Fluke testified before Congress in support of health coverage for contraception. We discuss the incident and assess Limbaugh's cultural and political influence.

For over 30 years Stanford neuroscientist Robert Sapolsky has combined field work on primates with neurological research in the laboratory, producing unique insights into primate and human behavior. Sapolsky joins us to talk about his latest research on stress and the brain.

As the first anniversary of the Fukushima Dai-ichi nuclear power plant disaster approaches, U.S. nuclear regulators are proposing new rules to improve safety. At the same time, they've just approved construction of two new reactors. We discuss the legacy of Fukushima, and how prepared we are to deal with the consequences of natural disasters at our nuclear power plants.

A recent study commissioned by the Girl Scouts found more than a third of girls surveyed between the ages of eight and 17 said they would not feel comfortable trying to be a leader. We look at the so-called gender ambition gap. What can be done to help raise strong and self-confident girls?

According to filmmaker Kevin Epps, most San Francisco residents haven't spent much time in his Hunters Point neighborhood. Epps' new documentary, "Straight Outta Hunters Point 2" is a sequel to his award-winning 2003 film. He joins us to discuss the film and his work in the community.

For the last two months, the Chukchansi Indian tribe in California's Madera County has been split over who should be the rightful leader of the tribal council. Like many other tribes, the Chukchansi runs a nearby casino. We explore the role that Indian casinos may be playing in provoking membership struggles within tribes around the country.

In the 1970s, UCSF's medical school made a series of notable advances in biological research, including the discovery of DNA cloning and the identification of the first cancer genes. Dr. Henry Bourne chronicles what he calls this "burst of discovery" in his new book, "Paths to Innovation."

Former San Francisco supervisor and mayoral hopeful Bevan Dufty has been appointed as the "Homelessness Czar" of San Francisco. He joins us to discuss his ideas, including how we should be more lenient with homeless alcoholics.