Prop. 8 advocates' appeal to parents could have been effectively countered by an immediate rebutal through TV ads, the study says. Same-sex marriage proponents need to be "preempting and rebutting rather than avoiding attacks that exploit anti-gay prejudice," the study says.

"to win, we need to understand why we have lost so many times," said David Fleisher, the study's author. "The data in this report give us clear explanations for why we keep losing, and having that insight is the first step toward victory in future elections."