Ernest Gellner made the point that - as a class - intellectuals are eunuchs (using a broad definition).
Ancient societies were (mostly) divided into warriors (rulers), priests (advisers, administrators/ clerks, lawyers), and peasants - and the priests were (in a sense) eunuchs.
In other words the intellectual elite are (over time) excluded from reproduction and leadership.
This was achieved in some societies by making actual castration a pre-requisite of obtaining the privileges of the intellectual class.
For example, in the Byzantine Empire (the most successful Christian Empire by far) the civil service was staffed by eunuchs - they formed a buffer zone between the Emperor and the rest of the world.
In Roman times most intellectuals were slaves.
In medieval Europe, the intellectuals were celibate (legally celibate, that it; they could not have legitimate heirs).
Another main class of intellectuals in medieval Europe were Jews, who were an encapsulated and subordinate population, legally excluded from rulership.
Most teachers have been of servant status: like 'nannies', private tutors or governesses.
In modern times, the intellectual elite (which includes a high-ish proportion of women) are of course de facto eunuchs: in the sense that they have opted for voluntary sterility with fertility delayed into the thirties and a fertility rates way below replacement levels; and in the sense that they are servants (who adjust to society) not leaders (who shape society).
(Indeed, there are no leaders at present; which is why things are set to revert.)
To be a eunuch, then, is to opt for a life of relative intellectual freedom and relative physical comfort; at the cost of near-zero fertility and subordinate (slave, serf, servant, outcast) status.
(I should emphasize that eunuchs may indeed, did indeed, have sex - as did celibate priests, slaves, servants etc; but they do not reproduce; or only at an insignificant level. Either they do not have offspring, or they are allowed to die, or are given/ taken away, or cannot inherit, or are confined in a ghetto, or something of the sort.)
The trend may be bucked for a generation or two - but equilibrium is soon restored: as we can see all around us. We are returning to the default of warriors, priests and peasants.
Of course, the present vast class of (pseudo) eunuchs - I mean intellectuals - cannot possibly be supported, and almost all of us will be returned to peasant status.
[There was, of course, another class: the middle class, the skilled trades and crafts and arts - the guilds or 'mysteries'. And these are not eunuchs but patriarchs. They provide the population to fill vacancies in the ruling classes, and leaders of the peasant classes. But the middle class have gone altogether. They will need to be rebuilt from the ground-up.]