The likelihood of a patent application being approved by the USPTO is significantly lower for female inventors than for male inventors, even within narrow technological groups. We investigate the reasons for this gap, focusing on the role of gender bias, and analyze the implications for the quality and value of the granted patents. We find that the gender gap in examiners’ first-action approval decisions declines significantly and becomes close to zero when inventor names are rare and thus more gender-blind. Additionally, granted patents authored by female inventors are associated with higher estimated market values, but this difference diminishes for the gender-blind group—a pattern also reflected in forward-citations. Consistent with the effects of statistical discrimination, the gender gap in approval rates is smaller for more experienced inventors and in technological art units with higher female representation. We estimate that more than half of the residual gender gap in the patent grant rates can be attributed to gender bias. Our findings shed light on the causes of gender differences in patent examination outcomes and offer implications for policies aimed at creating a level playing field in patenting.