There are good reasons to delay desexing in dogs, particularly large breed dogs. There is a significant link between early age desexing in large breed male dogs and the development of osteosarcoma.
Dogs desexed early often grow taller than I desexed dogs of the same breed.
There seems to be less evidence of negative impacts on cats, and an experienced vet can safely desex kittens at 1kg.
Of course delay in desexing can have larger implications for populations, which is why rescue animals are routinely desexed early.
theconversation.com/why-decisions-to-desex-male-dogs-just-got-more-complicated-95520
www.ncbi.nlm.nih.gov/pmc/articles/PMC6070019/
I wrote the comment about early desexed dogs growing taller and it occurred to me to wonder if there had been any work done on the psychology of castrati. As it happens, there has been.
“That “castrati” were particularly tall has been known since antiquity22, even Aristotle observed that “all animals, if operated on when young, become bigger than their unmutilated fellows”23. At the beginning of the XX century, the Skoptzy, a Christian sect practicing male castration, were measured and they appeared to be taller than their peers24.”
www.ncbi.nlm.nih.gov/pmc/articles/PMC4923859/
And I found this information.
“Although castration did little to damage a castrato's intellect, it did pose serious health and emotional problems otherwise. Most castrati suffered from the effects of developmental hypogonadism, including an infantile penis and underdeveloped prostate. They also had a greater presence of subcutaneous fat than the normal male, as well as fat deposits localized on the hips, buttocks, and breast areas, and also fatty deposits on the eyelids. These excess deposits of fat often caused their skin to appear wrinkled or swollen.
Castrati tended to be volatile, conceited, and almost impossible to get along with. Composer George Frederick Handel’s notorious shouting matches with his castrato Senesino, for instance, were well-known throughout England. Many of the castrati’s well-documented personality disorders were a direct result of their disfigurement, as well as their inability to lead normal sex lives. Despite public admiration for their singing, they were also prone to much ridicule regarding their physical condition.”
www.newworldencyclopedia.org/entry/Castrato
The disorder of personality might suggest that children castrated prior to puberty retained the narcissism of children and their lack of emotional stability.
This is just from 15 minutes research - so only guesswork really. But the human endocrine system is such a complex one, interwoven with every other system in the body, that removing one set of hormones and replacing them with another, seems a bit like taking a hammer to a window.
You’ve still got some bits, but the whole thing will never function properly again.
This is a terrible set of irreversible medical experiments being performed upon children without any clear idea of long term consequences.
I’m sure that in a decade we’ll look back in horror at this, in much the same way as we do other kinds of dangerous medical interventions driven by social hysteria.