A new study looks at correlation between college majors and religious practices (or lack thereof). A few findings:
Being a humanities or a social science major has a statistically significant negative effect on religiosity -- measured by either religious attendance and how important students consider the importance of religion in their lives. The impact appears to be strongest in the social sciences. Students in education and business show an increase in religiosity over their time at college. Majoring in the biological or physical sciences does not affect religious attendance of students, but majoring in the physical sciences does negatively relate to the way students view the importance of religion in their lives.
Thoreau complicates the data.