In the Goldwater chapter of Almost President: The Men Who Lost The Race But Changed The Nation, the book states Rockefeller could have prevented Goldwater from getting the GOP nomination but his wife, who he married soon after she divorced a prior husband, gave birth to their child around the time of the California primary and that dredged the scandal up again.
Despite this, Rockefeller had a good showing in California but still lost.
So what if the conception of Rockefeller's baby had gone somewhat differently and either the kid isn't there or is born earlier or later? The book states Rockefeller winning California could "derail" Goldwater, but doesn't go into detail how.