Research about students' viewpoints regarding STEM fields mostly address two target groups: physics/mathematics/engineering areas and undergraduate students. The purpose of this paper is to explore 9th-grade students' perceptions about biology and some of the factors and players that influence them in pursuing an academic or professional career in these fields of knowledge. A 13-item survey graded on a 5point Likert scale was administered to 350 Mexican students from two states, Chiapas and Nuevo Leon, as part of a broad research project that aims to determine which factors and players influence the perceptions of teenagers, from a gender perspective, about STEM fields. Results show statistically significant differences among group participants in the perceptions of the value of biology to their academic futures (T-Test, p=0.035) between genders in the state of Nuevo Leon (T-Test, p=0.037, 0.083). Results also show significant correlation between parents' levels of education and students' selfefficacy (Pearson correlations). Conclusions drawn from this paper discuss the relatedness of teenagers' STEM perceptions and their academic and professional futures with respect to gender, geographic residency, family and self-efficacy. The research also highlights the need for a profound comprehension of students' appreciation for science, technology, engineering and mathematics.