The Sociosexual Orientation Inventory (SOI) was not designed to illuminate the sexually dimorphic mental mechanisms posited by evolutionary theories. Its results are therefore open to competing interpretations. Measures designed to tap the thought processes surrounding sexual experience generate findings that are more compatible with evolutionary than with social structural theory.

Simpson and Gangestad's (1991) Sociosexual Orientation Inventory (SOI) is pivotal in Schmitt's cross-national study on sociosexuality. Here I elaborate on psychometric shortcomings of the SOI that are crucial in this research context.

My response to the commentaries highlights three main points. First, the Sociosexual Orientation Inventory (SOI) has demonstrated adequate reliability and validity across dozens of studies, and it deserves its reputation as a useful measure of basic human mating strategies. Second, the sampling limitations of the International Sexuality Description Project (ISDP) do not negate the conclusion that sex differences in sociosexuality are likely universal across cultures. Third, the ISDP results support several theories of human sexuality, although some are based on faulty assumptions that render them less viable than others.