Why are so many girls becoming pregnant in Brownsville, Texas? I encountered this question as a result of my field work. Teachers, school administrators, community officials, parents, and even students pose this question as part of a local concern over the high birth rate among Brownsville youth. As a response to this concern, I engage with this overarching research question by exploring the sex lives and romantic experiences of young mothering teens in Brownsville, through in-depth interviews and focus group discussions. However, as part of a larger mission of problematizing common misconceptions and misunderstanding regarding Mexican-origin youth and their sex lives, this thesis offers a Chicana feminist/borderlands analysis of what the young women shared concerning their sexual experiences. Through their stories, I situate teen pregnancy as a symptom of a complex web of discourses, practices, social institutions, and ideologies regarding sex, thereby elucidating the socio-cultural factors that make young Mexicanas vulnerable to unprotected sex, and consequently unintended pregnancy in Brownsville, Texas. Throughout this thesis I focus on three social and personal venues that stood out as the most influential sources from which my informants learned and talked about sex: peers, mothers, and boyfriends. Contrary to the culture of silence presumed by the literature, the mothers and peers of the young respondents are quite vocal about sex; in fact, there is strong peer pressure for young women to have sex. However, they are expected to so within the context of a committed, heterosexual relationship in which young women give into male desire. This set of social expectations compels young women to have unprotected sex, but also to engage in unwanted sex. In the final chapter, I suggest how sex education can be improved and tailored to the particular needs of Brownsville youth—that is both women and men. / text