UCSF researchers have discovered a human gene that can be traced back through the mouse to the fly, illuminating a molecular nugget from ancient times that may play a crucial role in male fertility - and infertility.

Scientists have identified the gene that prompts embryonic stem cells to generate precursors to most internal organs.

UCSF researchers have found that HIV-infected homeless and marginally housed people who have trouble sticking to their antiviral regimens may temporarily delay the onset of full blown AIDS if they manage to take at least half of their anti-HIV medications.

Some postmenopausal women carry a gene sequence that may lower their risk of breast cancer, according to new research from San Francisco Veterans Affairs Medical Center.

A recent increase in severe reactions to the street drug "Ecstasy" has prompted the San Francisco division of California Poison Control System (CPCS) to renew alerts about the drug's dangers.

Cancer screening guidelines that recommend a test based on age are too simplistic, argues a new study from the San Francisco Veterans Affairs Medical Center.

HIV-positive women are three times more likely than other women to develop lesions that can lead to anal cancer, new research shows. The greater risk is due at least in part to weakened immune defenses against the common sexually transmitted human papillomavirus (HPV).

HIV that has become resistant to powerful drugs called protease inhibitors may not be a dire sign of decline after all, researchers from the Gladstone Institute of Virology and Immunology have shown.

Many older adults dread colon cancer screening, because the most effective screening tool, colonoscopy, is uncomfortable and invasive. A new study from San Francisco Veterans Affairs Medical Center shows that a faster, safer, and potentially more pleasant technique works just as well.

A single exposure to cocaine triggers a week-long surge of activity in a brain region central to the development of addiction, according to new research on mice published this week in Nature. The changes may prime the brain for addiction, the researchers say.