Gender discrimination is defined as: “Any distinction, exclusion or restriction made on the basis of sex which has the effect or purpose of impairing or nullifying the recognition, enjoyment or exercise by women, irrespective of their marital status, on the basis of equality of men and women, of human rights and fundamental freedoms in the political, economic, social, cultural, civil or any other field.” [United Nations, 1979. ‘Convention on the Elimination of all forms of Discrimination Against Women’. Article 1]
Discrimination can stem from both law (de jure) or from practice (de facto). The CEDAW Convention recognizes and addresses both forms of discrimination, whether contained in laws, policies, procedures or practice.
De jure discrimination
E.g. In some countries, the law states that women (citizens) who marry foreign men lose their citizenship and/or property rights. On the other hand, men (citizens) married to foreigners do not lose their citizenship and/or property rights.
De facto discrimination
E.g. The practice of many immigration officials in various countries is to find a woman traveling alone with her minor children "suspicious" while men traveling with their children are seldom questioned.