This course is the first semester of a two-semester introduction to women's, gender, and sexuality studies, that considers the origins, diversity, and expression of gendered and sexed individuals. Topics include the evolutionary origin of sexes; evolution, development, and social construction of sex, gender, and sexuality; sexual difference, similarities and diversity in bodies, brains, and behavior. This interdisciplinary introduction is the required year-long gateway sequence for the minor in Women's, Gender, and Sexuality Studies. Students who complete both halves of the two-semester sequence WS 101/102 receive divisional studies credit for two courses, from two different divisions: Natural Science (without lab), Social Science, and/or Humanities. Neither WS 101 nor WS 102 alone carries divisional studies credit. Effective Fall 2018, this course fulfills a single unit in each of the following BU Hub areas: Philosophical Inquiry and Life's Meanings, Scientific Inquiry I, Critical Thinking.