"Paul Cameron, a former University of Nebraska assistant professor who now heads a group called the Family Research Institute, claims that gay men have an average life expectancy of 43 years.1 He and his co-authors calculated that figure by checking urban gay newspapers for obituaries and news stories about deaths. But as Walter Olson pointed out in Slate last December, this method produces an unrepresentative sample that includes only those who die; gay men of the same generation who live longer aren't in the sample at all! The sample also is biased toward urban gays who have AIDS and have come out of the closet."

Citation: http://www.columbia.edu/cu/21stC/issue-3.3/ross.html