"Biologically incapable of total objectivity"

I was reading the book The Polk Conspiracy by Kati Martin, a book about the CBS reporter George Polk. His story is dramatic and exciting enough I almost missed a short passage about NBC. I'll quote it here:

"The News Business, too, had been shaken by the war. The Washington press corps, swollen from a prewar few hundred, was now two thousand strong. Women had joined the ranks of journalists, though they were conspicuously absent from the airwaves. NBC News confidently pronounced women biologically incapable of total objectivity" and refused to put them on the air."

I could find no reference for the statement. But i found the exact same language in the epitaph of David Brinkley by Bart Barnes also of the Post.

"There were profound social and cultural changes stirring in the wings, but they had not yet found a place on stage. Women were moving into the workforce, but on a restricted basis. They could be hired for back room jobs in the media, but rarely out front. They were not permitted to broadcast at NBC. Management considered them “biologically incapable of total objectivity.”

Same exact language, same lack of source. Brinkley was also a radio news caster. In fact Brinkley authored the book Washington Goes to War, where he makes essentially the same attribution twice. Once on page 186 and this variation on on page 71.

"...for the first time great numbers of women who were hired, often reluctantly, to replace the men gone into the military. But NBC, among others, still would not allow them to broadcast news on the air because it considered them biologically incapable of exercising authority or making decisions."

It also appears in part in the book Suddenly: The American Idea Abroad and at Home 1986-1990. I have yet to find the original source for this NBC policy. If any reader has it I'd like to read it.