Why limit it to infants? That trouble creating six year old is certainly not yet a fully formed adult. What of the elderly no longer capable of contributing to the maintainence of my lifestyle? All this reverence toward human life is so 20th century.
To borrow the quote “the story 1984 was a warning, not an instruction manual”; the story “The Pre-Persons” was a warning, not an instruction manual.
In “The Pre-Persons”, you could have kids put to sleep up to the point where they could understand abstract thought - in the story, that was defined as ability to do algebra. An adult decides to challenge this system, by saying he had a head injury and forgot upper math.