Californians are set to vote on a proposal to spend $300 million a year over the next 10 years for stem cell research. For some perspective on how big a deal this would be, the federal government spent $25 million last year. The ballot measure, known as Proposition 71, is being financially supported by a strong cadre of entertainers, business people, and others, including Nancy Reagan, as the New York Times reports today and would be a strong counteraction to the Bush administration’s ban on new stem cell lines. But is the Times overstating the number of potential beneficiaries of stem cell research? The paper writes, “half of California’s families are affected by one or more of the 70 diseases or conditions that could respond to stem cell therapies,” in which they include Alzheimer’s disease. (Approximately 500,000 Californians have Alzheimer’s disease.) But as the Washington Post reported in June, stem cells are an unlikely therapy for Alzheimers, which involves the loss of huge numbers and varieties of the brain’s 100 billion nerve cells. Lest California voters come to wonder just what they’ve been sold, it may be better to be up front about it in the first place.