A new study suggests that women’s lack of confidence in their math skills may be one reason for the gender gap in the STEM fields.

The study used a national survey of 5,000 college students enrolled in first-semester calculus. Among all aiming to pursue STEM careers, 35% of women reported that they did not understand calculus well enough to continue to the next semester compared to 14% of men. This results suggest a lack of confidence, rather than a lack of mathematical ability, may be responsible for the high drop-out rate of women pursuing STEM careers. The authors postulate that if women persisted in STEM at the same rate as men Starting in Calculus I, the number of women entering the STEM workforce would increase by 75%.

The study appears in PLOS One.