A big puzzle has been solved with regard to fertile XY female Akodon. There are 3 types of X chromosomes noted amongst these XY fertile female Akodon. One type of altered X chromosome results in XY Akodon becoming female. http://www.sciencedirect.com/science/article/pii/S1616504708000232 There are several species (including humans) where an X chromosomal gene or an autosomal gene results in an XY individual being female. Typically these individuals are not fertile. Therefore the finding of an altered X in fertile Akodon does not explain fertility in these heterogametic XY fertile females. The likely explanation remains to be self-synapsis during meiosis of a univalent X or perhaps pairing between the X and the Y during female meiosis. That fertility may be retained in these individuals has been suggested to be an adaptive mechanism to the needs of various populations. Such seems to be found also in XY fertile female mice and perhaps XY female humans. Although the article discusses the X variant as a mutation, a balance in the needs of both fertility and infertility in diverse populations and species suggest that there is still no reason why the XY female state needs to be conceptualized as a disorder or a DSD in any species.