Synopsis That the sexes are unequal, nobody will dispute. What precisely the differences between the sexes are is a more difficult question to settle. And how these differences, such as they may be, originated is even more difficult to determine. Nevertheless, theories concerning the origin of sex differences serve as a major vehicle for justifying particular policy recommendations concerning the status of women. It is therefore of crucial importance to critically examine the various competing explanations of the etiology of sex inequality and to determine the relationship between different theories and policy recommendations. This paper will therefore try to: (1) identify and differentiate between the major types of theories concerning the origin of sex inequality; (2) criticize these theories; (3) examine the policy recommendations they lead to, and (4) examine the logical connection between theories concerning the origin of sex inequality and policy recommendations in principle. Any theory concerning the origin of sex differences has at least two components: it identifies what the major sex difference(s) is(are), and it explains its(their) emergence. Both components are, of course, linked to each other. Different identifications of sex differences lead to different explanations of their origin. We can typologize theories concerning the origin of sex inequality either on the basis of the major sex difference whose origin is explained or on the basis of the type of explanation. Here we shall classify the theories on the basis of the logic of the explanation rather than on the basis of the nature of the sex difference that has been defined as most important. The four different theoretical approaches that will be discussed are (a) the evolutionary theory, (b) the biological theory, (c) the economic theory, and (d) the cultural theory. In each instance, we shall draw on at least two major proponents. Any one author, however, might easily fit into more than one category.