The underrepresentation of women in Science, Technology, Engineering, and Mathematics (STEM) fields is well-documented and enduring (Huang et al. 2000; National Science Foundation 2004, 2011), particularly in fields that require extensive mathematical training (Ceci & Williams 2010). Attempts to identify the source of the gender gap have indicated that causes range from interactional (Bergvall & Remlinger 1996) to institutional (Moss-Racusin 2012). Some research has suggested that the perception of STEM fields as "unfeminine" reduces young girls' interest in them. This idea positions expert STEM identities as at odds and incompatible with feminine identities (Thomas-Hunt & Philips 2004). Using data from a large ethnographic study on the cultural and linguistic practices of high-achieving math and science undergraduates at a public university in Southern California, this thesis argues that mathematical expertise can indeed be enacted along with a range of feminine personae.

Focusing on three female students who regularly show expertise in their small peer groups in a multivariable calculus course, I argue that each woman enacts expertise while performing different gendered styles. One student claims a more traditional nerd girl identity, eschewing slang and traditional forms of feminine material self-presentation and using a formal mathematical register and unmarked intonation. The second student, while often forceful that she is right, employs a marked nasal whiny intonation when contesting the teaching assistant's decisions and advice, constructing a kind of childlike cute femininity. The third student enacts expertise within her otherwise all-male peer group, and physically presents herself as more emblematic of youthful, middle-class femininity while employin non-interrogative rising intonation, a practice often ideologically seen as feminine. This study shows that a range of feminine styles is not incompatible with expert STEM identities.

This research implies that for STEM educators concerned with gender equity, by recognizing that expertise can be accompanied by any kind of gendered persona, women should be encouraged to explore career paths in STEM fields without feeling that they need to conform to a certain type of feminine style.