Section 2. Processing of special personal data Article 16 It is prohibited to process personal data concerning a person's religion or philosophy of life, race, political persuasion, health and sexual life, or personal data concerning trade union membership, except as otherwise provided in this Section. This prohibition also applies to personal data concerning a person's criminal behaviour, or unlawful or objectionable conduct connected with a ban imposed with regard to such conduct. Article 17 1. The prohibition on processing personal data concerning a person's religion or philosophy of life, as referred to in Article 16, does not apply where the processing is carried out by: a. church associations, independent sections thereof or other associations founded on spiritual principles, provided that the data concerns persons belonging thereto; b. institutions founded on religious or philosophical principles, provided that this is necessary to the aims of the institutions and for the achievement of their principles, or c. other institutions provided that this is necessary to the spiritual welfare of the data subjects, unless they have indicated their objection thereto in writing. 2. In the cases referred to under (1)(a), the prohibition also does not apply to personal data concerning the religion or philosophy of life of family members of the data subjects, provided that: a. the association concerned maintains regular contacts with these family members in connection with its aims, and b. the family members have not indicated any objection thereto in writing. 3. In the cases referred to under (1) and (2), no personal data may be supplied to third parties without the consent of the data subject. Article 18 1. The prohibition on processing personal data concerning a person's race, as referred to in Article 16, does not apply where the processing is carried out: a. with a view to identifying data subjects and only where this is essential for that purpose; b. for the purpose of assigning a preferential status to persons from a particular ethnic or cultural minority group with a view to eradicating or reducing actual inequalities, provided that: 1º. this is necessary for that purpose; 2º. the data only relate to the country of birth of the data subjects, their parents or grandparents, or to other criteria laid down by law, allowing an objective determination whether a person belongs to a minority group as referred to under (b), and 3º. the data subjects have not indicated any objection thereto in writing.