What causes rabbits to spontaneously change gender?

Question

Working with rescued rabbits we often have people who purchased two girl (or boy) bunnies from a pet store or breeder, and a few months later they have a bunch of baby bunnies that need new homes.

I have heard this reported multiple times, in fact the majority of baby bunnies that enter the rescues in my area are the result of a spontaneous gender change of one of the rabbits. According to Wikipedia it is known to occur with animals as complex as chickens, but it does not mention rabbits.

Answer 1

As stated here, they don't change gender. Rabbits are one of those species whose gender is difficult to tell, especially in young animals, and therefore are regularly misidentified.