Why are there more women in some STEM fields than in others?

Why is it that there are more women in biology than there are in computer science in North America? Women in the biomedical fields are now earning more than 50% of undergraduate degrees in the US [1].

Biology, like computer science, was once stereotyped as masculine. Medicine continues to be stereotyped as masculine, especially fields such as surgery. Why has biology attracted so many more women than computer science?

To answer this question, I'll be synthesizing the findings of Cheryan's "Understanding the Paradox in Math-Related Fields: Why Do Some Gender Gaps Remain While Others Do Not?" [2], Cohoon's "Women in CS and Biology" [3], and Carter's "Why students with an apparent aptitude for computer science don’t choose to major in computer science" [4].

Between these three papers, four themes emerge for why women choose one STEM field over another:

1. Exposure to the field
2. Expected value of the major
3. Lack of prejudice in the scientific culture
4. Prospects of raising a family in that scientific culture