Your advice to Women’s Rights on 5/15 is very poor. Your response implies that similar jobs provided by people with similar qualifications are entitled to the same pay. Prudence, this simply isn't true. The only facts that you have are:
1. Both are interns.
2. They both provide similar services to the company that employs them.
3. One intern is a young man, the other a young woman.
4. There is a $1 per hour difference in their pay.
5. The young woman makes less money.
Some things that aren't clear:
1. if the young man has been at the job longer
2. if he has some taken some classes or gained some meaningful experience that have value to the employer
3. if the young man is a member of an influential family in the community (this is unethical, but not illegal)
4. if the young man dressed nicer or made a more professional impression at the interview
This is only a small list of potentially influencing factors.
You are doing a disservice to your readers by asking them to believe that there it is not legally permissible to pay people with different genders different wages. It is only illegal when one group (race, religion, gender, etc.) isn't afforded the opportunity and the conditions to achieve equal pay.
When I first became a manager, I discovered that one of my best employees (a woman) was being paid what I thought was too low a salary given her experience, her tenure, and the level of work that she was performing. I reacted emotionally (much like you are doing with your response) and took this issue to my boss. He responded by telling me that any person's salary is 50% a reflection of their skills and experience, and 50% a reflection of their willingness and ability to negotiate. I thought that this was sound guidance, and I used it to coach my employee. After a little work, she became able to articulate her true value to the company to senior management, and was awarded a salary in line with her peers.
The most troubling aspect of your response is that you are coaching your reader to pursue additional compensation as a matter of entitlement. Prudie...this approach will NEVER EVER work. Rather, she should approach her boss and ask for a review of her current performance along with a stated goal of getting a $1 per hour raise. If then it becomes clear that a raise to parity with her co-worker isn't available to her or the terms of that raise are far out of line with what her co-worker contributes, she then has evidence for a complaint.
She should then file that complaint with the school through which the intern program is sponsored (as you suggest). They have leverage. She alone does not. As romantic as it may sound to attempt become the Susan B. Anthony of the world of internships, charging into her supervisor's office with the passive/aggressive stance that you suggest ("Gee, it makes me wonder if there might be some unconscious gender bias at work here") will most likely only serve attach to her the brand of a malcontent with an unhealthy sense of entitlement. And like it or not, those brands have a way of following you around your town and your career.