“A survey of over 3,000 Californians conducted by the Public Religion Research Institute in June has found that Catholics strongly support the legal recognition of homosexual unions.”
Not knowing anything about the respondent selection process (who were the 3,000 and how were they selected), the demographic composition (gender, race, religion, ethnicity, income), and factors of behavioral attributes such as “church attendance”, and manner others, that had to be present in the dataset of the survey - whether asked or not - there is no way of knowing how scientific it is, or not, to apply any of the survey results to the broader California population. Because there is no way of knowing how representative the survey’s 3,000 respondents are to that population.
So, what is the agenda of those who did the survey? That might tell you how much science might or might not be in the selection of the 3,000.
The last time they voted. 52 percent said no to homo marriage. That's what counts. this is just a push poll to marginally sway opinion.