Can you marry your sibling?
Many states outlaw sexual relationships between siblings and between parents and their children, and no state allows siblings to marry. In some states, such as Oklahoma, such relations are punishable with prison sentences.
While cousin marriage is legal in most countries, and avunculate marriage is legal in several, sexual relations between siblings are considered incestuous almost universally. Sibling incest is legally prohibited in most countries worldwide. It was historically practiced in ancient Egypt and Inca tribes.
If one pair of siblings is married to another pair of siblings, the siblings-in-law are thus doubly related, each of the four both through one's spouse and through one's sibling, while the children of the two couples are double cousins.
This type of relationship is sometimes called βdouble first cousinsβ. The kids would end up being about twice as related as regular first cousins (who share 12.5% DNA). And at 25% shared DNA, that would make them about as related as half siblings. Keep in mind that this is only on average.
There is a country where you can marry your sibling, and in fact, there are a few. The countries where you can marry your sibling under certain circumstances are Argentina, Brazil, Thailand, and the Netherlands, with some exceptions in the laws of those two last countries.
DNA testing has revealed that a teenage brother and sister had a baby together in Northern Ireland. The little boy, who is now a toddler, was born in 2012 as a result of the siblings' incest. His mother was aged just 13 when she became pregnant, while his father β her older brother β was 15.
State | First cousin marriage allowed | Sexual relations or cohabitation allowed |
---|---|---|
Alaska | No | Yes |
Arizona | Only if both parties are 65 or older, or one is infertile | No |
Arkansas | No | Yes |
California | Yes | Yes |
Among the forbidden couples are parent-child, sister-brother, grandparent-grandchild, uncle-niece, aunt-nephew, and between half siblings and certain close in-laws. This "Levitical law" is found in Leviticus 18:6-18, supplemented by Leviticus 20:17-21 and Deuteronomy 27:20-23.
In humans, it's associated with consanguinity and incest, in which close relatives have sexual relationships and children. Inbreeding violates modern social norms but is fairly common in animals and plants. While inbreeding generally is considered negative, it also offers some positive effects.
The risk for passing down a genetic disease is much higher for siblings than first cousins. To be more specific, two siblings who have kids together have a higher chance of passing on a recessive disease to their kids.
Can I marry my sister in America?
Siblings cannot marry in the United States
Many states outlaw sexual relationships between siblings and between parents and their children, and no state allows siblings to marry.
Consanguinity β blood relationships
You may not marry your: Grandmother or grandfather. Mother or father. Father's sister (aunt) or brother (uncle)

#1 (Article 733)] Lineal relatives by blood, collateral relatives within the third degree of kinship by blood #2, may not marry, except between an adopted child and their collateral relatives by blood through adoption. #3 (Article 734) Lineal relatives by affinity may not marry.
X.: According to John Beckstrom, professor of family law, Northwestern University Law School, it is not legal anywhere in the United States for a father and daughter to knowingly marry each other. Such a marriage would not be valid. In fact, in many states the father would be prosecuted for criminal incest.
The law bans marriage between close relatives, which is defined as lineal relatives, blood relative in the direct line of descent, and collateral relatives, such as cousins or uncles, to the third degree of relationship.
Alabama Marriage Requirements
You cannot marry children, siblings, parents, uncles, aunts, grandchildren, grandparents or great grandparents of any relation. You can marry first cousins without restriction, however.
Answers (2)
Yes assuming you are Hindu, you will be governed by Hindu Marriage Act and according to this Act, you are not related to each other within the degrees of prohibited relationships, hence you can marry her.