I remember very clearly when the figure of speech “the mother of all X” came into English. It was during the first Gulf War, and Saddam Hussein gave a speech threatening the US-led alliance with “the mother of all battles” should they have the temerity to attack. I recall how the phrase was so strange that an area expert spoke on television, explaining that this was the literal translation of a somewhat flowery Arabic expression, used to evoke an exceptionally strong superlative.
Because, the thing about mothers is that they are a) important, and b) unique. Which makes it surpassingly odd that Trump propagandist and still-congressman Devin Nunes some time ago, in the context of Trump’s first impeachment trial, referred to the allegations against the president as
“one of the mothers of all conspiracy theories” to imagine that “somehow the president of the United States would want a country he doesn’t even like … to start an investigation into Biden.”
To paraphrase an old saying, “a victory has a hundred fathers, but a conspiracy theory has a hundred mothers”, apparently.