Merit should get priority in jobs

When will the employers treat male and female staff equally based on their merit and performance? Recently I was surprised to know about the wage discrimination prevailing in one of my close friend's workplace. It is not uncommon that female workers get lower wages than their male counterparts, although they contribute equally. I think employers should judge merit and performance while recruiting and paying the staff.
Nahida Farhana
Teacher
London-Bridge International School
Shyampur, Jurain, Dhaka