A lot of things could cause early marriage. One of the causes is family; some families could force their daughters to marry early, because it's one of the family cultures, or because of the poverty. Such as; in a very poor villages in Egypt, they found young girls has been forces to marry much older rich mans. Also other families protect their honor by marring their daughters as early as possible. Other reasons that some societies are under stress. Example; some African countries encouraged men, to seek young virgins.
The positive side in early marriage is a way to ensure that the wife is protected, and she's under the man control, and husband should work hard for her in laws. Parents feel that their daughters are safe with regular man. For example family in North Uganda, marry their daughter's young to dented family honor and protection, for themselves and the girl.
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