I'm thinking of charging extra because the customer is female.
That sounds a little sexist. Why because of their gender?
Women get free stuff all the time, they should pay more.
Charging a person more based on gender in not okay. There are laws against this kind of thing, you could get in trouble. Always charge the same price regardless of a customer's gender.
I don't care if it's not legal, it's going to happen now.
Then you risk losing your job, and possibly making your company look bad. Men get special treatment too sometimes, so it's not fair to start charging people because of their gender. It is important to strive for equality, and the little things like treating everyone the same are what brings it closer to fruition.