“…First, an analysis of research published during this time span reveals moderate but notable thematic shifts in the explanations of the underlying causes of the STEM gender gap at the undergraduate level. Specifically, the literature prior to 1980 tended to focus on structural barriers in K-12 (e.g., Fennema and Sherman, 1978), psychological factors, values, and preferences (e.g., Stein and Bailey, 1973), and family influences and expectations (e.g., Lipman-Blumen, 1972). In contrast, and discussed below, later research witnessed an increasing focus on students' backgrounds and their perceptions of STEM fields.…”