We conducted a mixed-methodological study of matriculation issues for African-American students in science. The project compares the experiences of students currently majoring in science (N= 304) with the experiences of those who have succeeded in earning science degrees (N=307). Using a 57-item Likert scale questionnaire, participants were asked about their experiences based on theories that are commonly used to explain matriculation issues (Stereotype Threat, Microaggressions, Communities of Practice). The results of the study revealed that although both groups recognized the major role of race in their experiences, the primary factor distinguishing between groups was a sense of alignment with the community (Communities of Practice) and their differences with experiencing Microaggressions. Those who achieved success were far more likely to report a weak sense of belonging and were far more likely to report experiences with Microaggressions. By contrast, students were more likely to feel comfortable with the science community and less likely to report experiences with Microaggressions. The findings of this study are indicative of the pervasive impact of racial bias and conflict as a gatekeeper in providing access to science careers.