Critser's book is a brilliant exposé of the increasingly popular anti-ageing industry and how its practitioners have misled many people into believing that they can stop or reverse the effects of ageing. Proponents seem to argue: ageing is your fault; we have an unproven cure for sale that no one has disproved; scientists and physicians who disagree with us operate in a failed paradigm; and our patients tell us they feel better, therefore our treatments work.

We were astonished to see two sentences in your Editorial on the International Human Epigenome Consortium (Nature 463, 587; 2010) that seem to disregard principles of gene regulation and of evolutionary and developmental biology that have been established during the past 50 years.