The establishment of a minimum wage benefits the lowest earners in the labour pool. These are overwhelmingly women and ethnic minorities.
Women account for roughly 49% of the US labour force, but make up 55% of workers earning less than $10.10 an hour.  Similarly, around 13% of the US population is black or African American and 18% are Hispanic or Latino, yet 22% of families earning less than 200% of the federal poverty level are black, and 30% are Hispanic.  The fact that women and minorities are overrepresented among the lowest earners means that they stand to gain the most from policies affecting the minimum wage.
[P1] Minimum wage laws help low-income workers. [P2] Women and ethnic minorities are overrepresented among low-income workers. [P3] Therefore, minimum wage policies reduce gender and racial income gaps.