It is a condition which is discrimination by definition by it is allowed by the law like the inherent requirement of a particular job is discrimination but it may be the need of that family, so it is a fair discrimination by law.
Discrimination is the allowance of goods, services, attributes to an individual who is not deserving it on the bases of merit.
There are types of discrimination in which some are allowed by the law and some are prohibited.
So the allowed discrimination are fair discrimination and others which are not allowed are known as unfair discrimination.
I think that discrimination is always unfair but in some cases is allowed by law or certain standards in some countries and when that happens it is called fair discrimination. Employers often employ young females instead of young males because in general they think that young women are more responsible than young men.