patrick.net

Most countries legally prohibit marriage between full siblings (brother and sister) due to strong incest taboos and genetic concerns, with major examples including the USA (at state level), China, South Korea, Taiwan, France, Italy, and Japan, though specifics vary, with some allowing half-sibling or distant cousin marriages, while nations like Brazil and Sweden have specific exceptions, often for half-siblings, and some Islamic countries impose death penalties for incest.

Countries with General Bans (Including Siblings)

United States: Varies by state, but full sibling marriage is universally banned; some states allow half-sibling or cousin marriages.

China (Mainland): Prohibits marriage for blood relatives up to the third degree, including siblings.

South Korea & North Korea: Restrict marriage up to third cousins.

Taiwan: Prohibits marriage up to second cousins.

France: Forbids marriage between brothers, sisters, half-brothers, and half-sisters.

Italy: Prohibits marriage between first and second-degree relatives (siblings, parent-child).

Japan: Bans marriage between siblings.

India: Has laws restricting uncle-niece, and by extension, sibling marriages.

Countries with Specific Exceptions

Brazil: Allows half-sibling marriage with health checks; invalidates full sibling marriages.

Sweden: Permits half-sibling marriage under specific conditions.

Varying Penalties

While some nations, like Afghanistan, Brunei, and Iran, have severe penalties (including death) for incest, these often depend on specific circumstances and whether the act is consensual.

In essence, while prohibitions are widespread, the exact degree of kinship banned and the legal consequences differ significantly across jurisdictions, with a general global trend against full sibling marriage.

gabbar says

Is marrying one's brother unlawful in our country? Just curious.

Death penalty for that under Islamic law. Even so, she committed immigration fraud.