I believe that I made allusions to the cargirl theory before. How else can multiplying carboys be explained. First you have one, then you make the fatal error and get a second. This second must bea cargirl in disguise! Before you know it you have a room full of them and are looking for new places to hide them from daylight. That could also be a mistake as I think they are using dark places to reproduce. This is just my theory but think that the fizzing sometimes heard during fermentation is really them conspiring against us.
Have you considered that your carboys may share similar reproductive capacities toa ‘perfect’ flower, whichhas both male and female components, also known as a ‘hermaphrodite’ or ‘bisexual’ flower?
I am having the same problem with not only my carboys, but my gender-neutral one-gallon jugs. Presently, they are multiplying in my bedroom closet, in kitchen cabinets, under the sink, under the wet bar, and in the food pantry. Given that I'm a divorced single male with two teenage daughters who would object to my having female roommates, I've always assumed they were male. I also can't imagine a female companion tolerating allthese friends hanging out in the dark corners of my place, especially in every part of the kitchen.