First of all, you just say it's impossible, without explaining how my mother could also have a memory of it when I had never told her.
It's extremely common for parents of male babies to get peed on that way. In fact, I remember at parenting class they specifically recommended having a towel nearby just in case.
So, assuming that you are a male, it's extremely likely that your parents would have a memory of such an event because that event was likely to happen and multiple times.
I can buy that the situation as you described it could have happened at some point. I don't know what age at which the require language and planning facilities develop though. I would think around 18 months at the earliest, but I'm not an expert.
Maybe our resident expert
TSQ knows?
Mr Awe
Addressing the development of language: There are a few different theories as to how language develops, but they all agree that it starts very early on...like, pretty much immediately upon birth, or even before birth depending on how much one adheres to versions of the nativist theory or interactionist perspective, both of which consider language as at least partially innate. There is mounting evidence to support the innateness of language. My stance is that, like any other aspect of human psychology, language development is a combination of nature and nurture.
Phonological development begins at birth. Infants are physically incapable of actual speech because of the anatomy of their mouths (the soft palate is closer to the epiglottis, which is why they are obligate nose breathers), but they do start to babble and there is plenty of evidence that they recognize the sound of their native language (this is not the same as understanding language). Babies younger than a year can recognize a handful of familiar words, and begin to use some gestures, and by several months to 1 year of age they do begin to comprehend simple language, however, recognition of correct pronunciation of familiar words doesn't really occur until 1-2, suggesting that the depth of their recognition is limited.
Babies go through an intense vocabulary development phase between about 18-24 months, during which their vocabulary grows to several hundred words, of all word types.
Grammatical development doesn't really start until 1-2. There is plenty of evidence that grammar is innate (I can go into that more if anyone is interested), however it begins to be employed between 1 and 2 years of age.
Even though babies understand more language than they are able to employ, a baby of 6 weeks would definitively
not understand the remark
Tiberus' father made even at the literal level. As for comprehension of why the remark was humorous, that wouldn't happen until much, much later. I don't have any experimental or definitive evidence to cite, but I spent 5 years working with children, primarily on language development, and I'd guess that a kid would have to be at least 3 or 4 before he understood why the remark was funny, and even that would be a stretch.
As for planning ahead, children under the age of 5 have a very limited concept of the future.
As to the point about the mother...Just because the mother confirmed she had a memory of the event doesn't mean it happened when and how she remembers it. Adults' memories are as flawed as kids'. As someone mentioned, kids pee on their parents all the time, this likely happened more than once at different ages, and the mother was remembering a different time.