While marriage between full siblings is legally prohibited in almost all countries worldwide, the answer isn't straightforward. In some cases, marriages between half-siblings are legally permitted, most notably in Sweden.
Legality and Moral Considerations
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Legal Prohibition: The vast majority of countries prohibit marriage between siblings (both full and half). This is based on legal, ethical, and genetic considerations.
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Sweden's Exception: Sweden has a specific exception where marriage between half-siblings is legally permitted, requiring a special permit. This is extremely rare and subject to strict conditions.
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Westermarck Effect: The Westermarck effect explains that people who grow up in close proximity to each other during childhood typically do not develop sexual attraction. This innate aversion is thought to contribute to the rarity of sibling marriage and incestuous relationships.
Why is Sibling Marriage Generally Prohibited?
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Genetic Risks: Children born from sibling marriages have a significantly higher risk of inheriting recessive genetic disorders. This is due to the increased likelihood of sharing the same harmful genes.
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Social Taboos: Strong social and cultural taboos exist against incest (sexual relations between close relatives) in virtually all societies.
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Ethical Concerns: Many view sibling marriage as morally wrong and harmful to family structures.
Examples of Legal Stance
| Country | Full Sibling Marriage | Half-Sibling Marriage |
|---|---|---|
| Most Countries | Prohibited | Prohibited |
| Sweden | Prohibited | Permitted (with permit) |
It's important to understand that even where technically legal (as in the case of half-siblings in Sweden with special permits), these marriages are incredibly rare and carry significant social stigmas.
