The evolution of sexual reproduction is a striking case of explanatory pluralism, meaning that one needs to refer to more than one explanation in order to adequately account for it. I develop the concept a domain of phenomena in order to analysis this pluralism. Pluralism exists when a phenomenon can be included in more that one homogeneous domain or in a heterogeneous domain. I argue that in some cases domain partitioning can be used to decrease pluralism, but that in the (...) case of sex domains are overlapping and interconnecting, or in other words bear an orthogonal relationship to one another, and hence cannot be partitioned in such a way as to eliminate pluralism. (shrink)