Though Alzheimer disease (AD) has been recognized as a distinct entity since 1907, scientific understanding of, and public interest in, the disease remained very limited until the 1970s. The perception of AD as a significant problem has been substantially affected by cultural and demographic changes and by interest group and federal government initiatives. The recognition of AD has transformed senility from an expected stage of life into a "disease." It has also increased fear both of the individual effects of having AD and of the social consequences of AD in the population. Both the biotechnology industry and AD activist organizations will play a role in the social implications of genetic testing for AD.