This ero adaptation of a popular children's fairy tale was brought to us, courtesy of the letters: "W", "T" and "F" (which gives us the acronym: "What The Fuck"), as well as the letter "D", the first letter in the word: "DAYUM!"
Of course, if the rest of the series from whence this came ever gets an English translation, I'll be lined up to check them out.
He calls her mother cause, you know, she's a mom? With a kid? Calling your wife mother is a super common thing in anime/manga, and I'm pretty sure I've seen it outside of japanese culture too from time to time. It has nothing to do with pseudoscience that's been disproven for like a million years.
@Lord Dashwood Dude this is a super old trope older than time itself. Kana Imouto did it and that's from 1999. Literally 2 decades ago.