Though Americans say they are very interested in new medical advances, they aren't always familiar with individual developments. Questions on specific issues can yield a higher-than-average number of "don't knows." Seven in ten Americans say they know little or nothing at all about genetic mapping, which has been heralded as a key medical breakthrough with significant implications for researchers, doctors and the general public, and many Americans say they are not sure about the impact of genetics on medicine. Survey researchers often consider a double-digit "don't know" response a warning sign that an issue may not be well understood and opinion may not be stable. Public attention to one complex issue, stem cell research, has increased substantially over the past few years. In 2001, when the debate first broke into the news, six in 10 Americans admitted they weren't following the issue closely. By 2005, 58 percent said they followed stem cell news at least "somewhat closely." While majorities say they support stem cell research, question wording can influence results, which suggests there is still some uncertainty on this question.