Did this study go into the reasons why that that is true?
No, but it was while I was on TR and was published in either Proceedings or Navy Times. A week or so later, the yearly flag promotions came out and both Capt Abbott (TR CO) and Capt Fallon (CAG) were on the list. Both had fathers that were flags and in Abbott's case Grandfather and possibly Great Grandfather. The night the list came out, I was passing through Combat on my way to OOD watch. TAO told me about their selections and I said "it figures, their Dad's were Admirals".. Next thing I know Capt. Fallon has me cornered and is chewing me a new asshole (bad SA on my part). Later on the bridge, Capt. Abbott called me to his chair and told me not to worry about it. He said while he thought his performance justified his selection, there was no doubt his lineage played a part in his career/assignments. I explained to him about the study I'd recently read and he said it was an indisputable fact and CAG Fallon knew that too.
Admiral Abbott - definitely deserved every promotion he ever got. One of the best Naval Officers I ever met and served under.
Admiral Fallon - not so much.
So even though I don't know "Tom" and he may be the best stick around, I'd bet when his selection wish list popped up someone said "the Admiral...." It's something that he will have to live with and acknowledge his whole career. How he handles this will be the measure of his character. From what those who know him on here have posted, he seems to be handling it right.
But don't ever believe that his CoC doesn't know who his father is or that this fact escapes them at decision time.