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 5-point 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' self-efficacy (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.