According to Rev. William Barber: The Fight for a $15 Minimum Wage Is a Fight for Racial Justice. He says "We cannot address racial equity if we do not address the minimum wage of $15." To be fair he sort of mixed up.
But according to the U.S. BUREAU OF LABOR STATISTICS: Characteristics of minimum wage workers, 2018 (.pdf)
In short, it discriminates against youth. And that is exactly who would be harmed the most by an increase in the minimum wage....Age. Minimum wage workers tend to be young. Although workers under age 25 represented only about one-fifth of hourly paid workers, they made up just under half of those paid the federal minimum wage or less. Among employed teenagers (ages 16 to 19) paid by the hour, about 8 percent earned the minimum wage or less, compared with about 1 percent of workers age 25 and older. (See tables 1 and 7.)
Gender. Among workers who were paid hourly rates in 2018, about 3 percent of women and about 2 percent of men had wages at or below the prevailing federal minimum. (See table 1.)
Race and Hispanic or Latino ethnicity. The percentage of hourly paid workers with wages at or below the federal minimum differed little among the major race and ethnicity groups. About 3 percent of Black or African American workers earned the federal minimum wage or less. Among White, Asian, and Hispanic workers, the percentage was about 2 percent. (See table 1.)