Re: ucbalumnus #124: Of course, it is an advantage to have dual Ph.D. parents, relative to students who encounter high barriers to achievement.
I would guess that quite a few admissions staffers now are second-generation college, or more. One or both of their parents quite likely attended college. I was really referring to the possible advantages that admissions staffers might not share, and how they interpret their values. In this context, I think that admissions staffers may overestimate the educational advantages conferred by having dual Ph.D. parents, relative to having one or both college-educated parents (but not both Ph.D.s).
A student with two parents in STEM is probably more likely than most to have completed multi-variable calculus pre-college. Parents who remember multi-variable calculus may be able to field a question or two that others could not. They may be more inclined to allow radical acceleration in math (or not). So that could be an advantage. But no one I know has acquired multi-variable calculus by osmosis, or simply growing up in a household where multi-variable calculus is known to the parents.