Class, gender was not originally scheduled to be included as a protected category in Title VII but was included as a final effort to thwart passage of the Civil Rights Act of 1964. Even though Title VII has been in effect for 50 years as of 2014, only 15% of women work in jobs typically held by men (engineers, stockbrokers, judges), while fewer than 8% of men hold female-dominated jobs, including the careers of nurses, elementary school teachers, and sales clerks.
Why do you think, not with standing a half century of Title VII enforcement, gender association with many jobs continues to this day?