Their rationale for this practice was to preserve their "royal blood", and this often had an adverse effect on their health; Charles himself was disabled, epileptic and mentally unstable.

The book discusses the genes responsible for some human traits, including red hair, earwax and lactose intolerance/lactase persistence.

Rutherford criticises the popular press for their inaccurate reporting on genetics, and companies conducting genealogical DNA tests that produce impossibly accurate results.

In a review in The Guardian, Colin Grant described A Brief History of Everyone Who Ever Lived as an "effervescent work, brimming with tales and confounding ideas".

He said that Rutherford aims high: the rewriting human history, but called him "a commendable historian ... who is determined to illuminate the commonality of Homo sapiens".

Writing in another review of the book in The Guardian, McKie noted how the author is careful to bring the project's "dreams of a medical revolution" down to earth, emphasising that its "greatest achievement ... was working out exactly how little we knew.

[1] He was impressed by the way Rutherford dealt with such sensitive topics as race and eugenics, and that he used examples like earwax and lactose intolerance, rather than Mendel's exhumed pea plants to demonstrate how genetics work.

"[1] Nancy R. Curtis wrote in the Library Journal that A Brief History of Everyone Who Ever Lived should attract readers of both popular and technical science books.

[9] In a review in The Wall Street Journal, Charles C. Mann was a little critical of the book's title, saying that it "is not particularly brief, not exactly a history and not concerned with everyone who ever lived".