Chapter One[1] sufficed.
Mr. Foster is doing creative ontogenic work with the intention of introducing improvements to the status quo (and Huxley takes a sideswipe at "They will outbreed Us"[2]):
> "Sixteen thousand and twelve in this Centre," Mr. Foster replied without hesitation. ... "But of course they've done much better," he rattled on, "in some of the tropical Centres. Singapore has often produced over sixteen thousand five hundred; and Mombasa has actually touched the seventeen thousand mark. But then they have unfair advantages. You should see the way a negro ovary responds to pituitary! It's quite astonishing, when you're used to working with European material. Still," he added, with a laugh (but the light of combat was in his eyes and the lift of his chin was challenging), "still, we mean to beat them if we can. I'm working on a wonderful Delta-Minus ovary at this moment. Only just eighteen months old. Over twelve thousand seven hundred children already, either decanted or in embryo. And still going strong. We'll beat them yet."
and there is other creative work to be done, are other changes to introduce:
> Pilkington, at Mombasa, had produced individuals who were sexually mature at four and full-grown at six and a half. A scientific triumph. But socially useless. Six-year-old men and women were too stupid to do even Epsilon work. And the process was an all-or-nothing one; either you failed to modify at all, or else you modified the whole way. They were still trying to find the ideal compromise between adults of twenty and adults of six. So far without success. Mr. Foster sighed and shook his head.
No problem with utilitarianism, even if they move a different lever for utility than we do (or do they? compare https://news.ycombinator.com/item?id=24097162 ):
> "And that," put in the Director sententiously, "that is the secret of happiness and virtue–liking what you've got to do. All conditioning aims at that: making people like their unescapable social destiny."
(As Huxley wrote 30 years before the Cleese + Ronnies sketch[3] his idea of social destiny may have been a bit more predetermined than our twenty-first century bien-pensant ideas on the subject.)
[1] https://www.huxley.net/bnw/one.html
[2] Körner notes that no matter what kind of Darwinist: Social, Economic, Academic, etc., they may be spotted by their constant undarwinist worry that the unfit will outbreed the fit.
[3] https://twitter.com/johncleese/status/1254130854462455813?la...