Bioethics is an important aspect of the core competency of biology of understanding the relationship between science and society, but because of the controversial nature of the topics covered in bioethics courses, different groups of students may experience identity conflicts or discomfort when learning about them. However, no previous studies have investigated the impact of undergraduate bioethics students’ experiences in bioethics courses on their opinions and comfort. To fill this gap in knowledge, we investigated undergraduate bioethics students’ attitudes about and comfort when learning abortion, gene editing, and physician assisted suicide, as well as how their gender, religious, and political identity influence their attitudes and changes in their attitudes after instruction. We found that religious students were less supportive of gene editing, abortion, and physician assisted suicide than nonreligious students, non-liberal students were less supportive of abortion and physician assisted suicide than liberal students, and women were less supportive of abortion than men. Additionally, we found that religious students were less comfortable than nonreligious students when learning about gene editing, abortion, and physician assisted suicide, and non-liberal students were less comfortable than liberal students when learning about abortion. When asked how their comfort could have been improved, those who felt that their peers or instructors could have done something to increase their comfort most commonly cited that including additional unbiased materials or incorporating materials and discussions that cover both sides of every controversial issue would have helped them to feel more comfortable when learning about gene editing, abortion, and physician assisted suicide. Finally, we found that students who were less comfortable learning about abortion and physician assisted suicide were less likely to participate in discussions regarding those topics. Our findings show that students in different groups not only tend to have different support for controversial topics like gene editing, abortion, and physician assisted suicide, but they also feel differentially comfortable when learning about them, which in turn impacts their participation. We hope that this work helps instructors to recognize the importance of their students’ comfort to their learning in bioethics courses, and from this study, they can take away the knowledge that students feel their comfort could be most improved by the incorporation of additional inclusive materials and course discussions regarding the controversial topics covered in the course.