Narrator: This is Science Today. Since the 1980s, scientists have known that tobacco smoke puts unborn babies at higher risk for a wide variety of health problems, including heart defects and cancer. But just why this happens has been somewhat of a mystery. Now, researchers at the University of California, San Francisco, have used stem cells to create a better picture of how tobacco smoke affects early human development.
Bernstein: We found that whereas normally, embryonic stem cells will go on to develop into all the different tissues of the body, the very first steps in that process were disturbed when these cells were exposed to tobacco smoke.
Narrator: Study leader Harold Bernstein says the finding is the first step in understanding how tobacco smoke affects development at the molecular level.
Bernstein: The very earliest stages of development have a great impact later on. Defining these really early events that are susceptible to tobacco smoke really could spread a lot of light on how these birth defects occur.
Narrator: For Science Today, I'm Larissa Branin.