Sexual reproduction is notoriously complex in fungi with species able to produce sexual progeny
by utilizing a variety of different mechanisms. This is even more so for species employing multiple sexual
strategies, which is a surprisingly common occurrence. While heterothallism is relatively well understood in
terms of its physiological and molecular underpinnings, homothallism remains greatly understudied. This can be
attributed to it involving numerous genetically distinct mechanisms that all result in self-fertility; including primary
homothallism, pseudohomothallism, mating type switching, and unisexual reproduction. This review highlights
the need to classify these homothallic mechanisms based on their molecular determinants and illustrates what is
currently known about the multifaceted behaviours associated with homothallism.