Tuvalu

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4. Amongst the values that we the people of Tuvalu seek to maintain are those embodied in our traditional forms of community, the Falekaupule, and the strength and support of the family and family discipline.
... (Principles of the Constitution)

(1) In this section, discrimination refers to the treatment of different people in different ways wholly or mainly because of their different
(a) races; or
(b) places of origin; or
(c) political opinions; or
(d) colours; or
(e) religious beliefs or lack of religious beliefs, or
(f) disability; or
(g) sex
in such a way that one such person is for some such reason given more favourable treatment or less favourable treatment than another such person.
(2) Subject to the provisions of this Part, and in particular to
(a) the succeeding provisions of this section; and
(b) section 29 (Protection of Tuvaluan values, etc.); and
(c) section 31 (disciplined forces of Tuvalu); and
(d) section 32 (foreign disciplined forces); and
(e) section 33 (hostile disciplined forces); and
(f) section 36 (restrictions on certain rights and freedoms during public emergencies),
no-one shall be treated in a discriminatory manner.
(3) Subsection (2) does not apply to a law so far as it makes provision
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(d) in respect of-
(i) adoption: or
(ii) marriage; or
(iii) divorce; or
(iv) burial; or
(v) any other such matter,
in accordance with the personal law, beliefs or customs of any person or group; or
… (Sec. 27)

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(2) Under this Constitution every person has the following fundamental duties and responsibilities to themselves, their dependents, and others –
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(b) to uphold the Christian principles of a family unit, which shall comprise a marriage as between a man and a woman to the exclusion of all others, and their offspring as the foundation of the Tuvaluan society;
(c) in the case of parents, to care for and not neglect their children, and to teach children to uphold their duties, Tuvaluan ways of life, and Christian principles;
(d) in the case of children, to listen to and respect their parents, teachers and all people; to assist in the home and with their family; to do what they are directed to do, and to attend school and classes;
(e) in the case of husbands and wives, to perform their roles in upholding family values and communal society;
... (Sec. 43)