It is often said that when a child is toilet trained earlier in its life rather than later, it is not in fact the child who is trained, but the parents.
This is entirely stupid, as I will now prove.
The first factor which must be understood is that toilet training a child is the absolute worst task in childrearing. The absolute worst. It awakens a previously unwrathful parent to her own shockingly vast capacity for unmitigated wrath. It is the task most likely to make an at-home mother long to pay some other person (perhaps the drunkard across the street or an arthritic labradoodle, any arthritic labradoodle) to take over the care of her child. It is the task most frequently begun and abandoned. It is the task most often left to fall entirely on the shoulders of mothers, as fathers simply cannot handle it.
The second factor that must be understood is that diapers are SO DISGUSTING. A child on a normal human diet excretes exactly the same thing that normal humans excrete. At some point, the horror of having her face inches from this disgustingness every day of her life outweighs a mother's doubt as to her child's readiness. She cannot continue to change diapers. The child--whether or not he can talk or has expressed interest or has attained the necessary age du jour--must be housebroken. (NB: this is why children of an at-home mother are usually toilet trained earlier in life than children whose care is divided among different persons over the course of a day. The sole caregiver wears out faster.)
So a young child becomes a candidate for toilet use. And the mother must run all day long. She must keep the child off furniture and carpets. She learns that she can no more make her child excrete than she can make him eat, sleep, or be quiet. She must clean unspeakable messes from the rising of the sun to the going down of the same. If it becomes too much, she goes back to diapers until once again she is overtaken by that disgustingness. She tilts on the brink of madness for the duration of this period. Amen, amen, no one gets it.
However, many young children succeed. They are granted the excretory epiphany. They become users of toilets and wearers of underwear, and there is much rejoicing. But still the child is young. He cannot put on his trousers in the morning; neither can he rule them in the bathroom. He is too short to climb stairs, so also to scale toilets. He is too stupid to wash his hands in the kitchen: similarly the bathroom. Thus do parents (for the fathers have begun to return at this point) RUN RUN RUN to the bathroom when the child announces his need of it, and in so doing, appear to be slaves of an untrained child.
But only to those who do not realize that if a kid too young to dress and wash himself is able to discern and communicate his need for and carry out the act of eliminating in the toilet, wizardry must almost certainly be involved.
Only to those who have never changed a diaper, or have been so long from the task that its disgustingness has somehow been forgotten.
Only to those who know neither the expense of disposable diapers nor the labor of cloth diapers.
Only to those who are unaware that a dirty diaper must be changed as promptly as a young child's call for the bathroom must be attended.
Only to those who do not understand that the greatest hero on any day of human history is not the discoverer nor the inventor nor the orator, but the child who for the first time in his life refuses to befoul himself.