A brother or brother is a male relative, whose relationship has arisen by having a common mother and father.
Brothers who only have one parent in common are called half-brothers.
A step brother or step brother is a brother from another parent's marriage than from which one himself was shot. This occurs for example when a widow marries a widower. Step brothers do not have a common father or mother and so are not blood relatives.
A brother-in-law or brother-in-law is a male-married family member, whose relationship is caused by a marriage of the person himself, a brother or a sister. Housewives do not have a common father or mother and are therefore no blood relatives. Also see WikiWoordenboek
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