Title IX was designed to address gender equality in schools. However, research has revealed that traditional coed multi-activity programs do not always address female student needs (Bischoff, 1983; Griffin, 1984; Lirgg, 1993;1994) or provide equal opportunities (Allard, 1979; Strazulla, 1986). Furthermore, perceptions and behaviors within the classroom ecology are complex and reciprocal (Doyle, 1979). This study investigated the reciprocal nature of teaching and learning by comparing similarities and differences in perceptions and behaviors of middle school physical education teachers and students during coed and single gender invasion game units. Through this naturalistic inquiry, data on teachers’ perceptions and instructional behaviors, and students’ perceptions, task responses, and achievement were collected and qualitatively analyzed. Two veteran physical education teachers taught soccer and basketball units normally except for teaching longer instructional units in both coed and single gender settings. Coed classes included students randomly assigned from the original classes to avoid intact classes and ensure equal distribution of skill level. Each teacher was formally interviewed before and after instruction. All classes were videotaped for later coding of instructional and student behaviors. Student responses to instructional tasks were coded for congruence and success. Skill improvement was determined by pre- and post-skill testing. Skill test assessment tasks and rubrics were derived from the teachers’ unit goals. Student perceptions were obtained through formally interviewing three male and three female students (high, medium, and low skilled), randomly selected, after instruction was completed. Percentages for teacher behaviors and student responses and mean differences for student performance in skill tests were calculated. Audio-taped interviews were transcribed and analyzed using inductive analysis (Patton, 1990). Triangulating data points were determined through constant comparison (Glasser & Strauss, 1967) of all data. Findings indicate that tasks addressing the specific needs and interests of students’ based on gender were more salient to student outcomes than engaged time. Student processes and outcomes were best during single gender setting with same gender teacher. Both students and teachers perceived that single gender classes were best for learning. Findings indicate that male and female students have different instructional needs that same gender teachers may best be suited to meet and that single gender classes offer female students many positive opportunities that coed classes do not. Therefore, if the mission of Title IX legislation is to promote equitable learning opportunities, then teachers need to consider the benefits of single gender class compositions when planning school curricula. Keyword(s): curriculum development, gender issues, middle school issues