The first chapter of the present book lays the empirical foundation for the investigations undertaken in the second chapter. Essentially, the first chapter establishes the validity of the two MMPI-2 scales – Gender-Masculine (GM) and Gender-Feminine (GF) – in discriminating between sex types. The second chapter moves on to applying the GM and GF scales to two discrete clinical populations in firstly, examining cross-nation variations and secondly, focussing on the differences in gender roles or sex types. Both chapters uniquely contribute to the gender literature surrounding masculinity-femininity attributes by extending cross-nation investigations to subjects with mental illnesses. The first chapter is the only investigation applying the GM and GF scales to clinical subjects, while the second chapter is a unique cross-cultural attempt to examine masculinity-femininity attributes and then explain the variation in the context of culture-specific variables. Each chapter is a paper or study in its own right, and follows on with its respective literature review, methodology, results and discussion.