A single parent is a parent with one or more children, who is neither married, nor living together with his or her partners. Single mothers are far more common than single fathers. The definition of single parents may vary according to local laws of nations or provinces. But in typical cases, she or he may be so after divorce, after giving birth to a child outside marriage, or after his or her spouse died.
Some single mothers may have chosen to be so voluntarily but for some others it is the result of accidental pregnancy, while not wanting or not having the opportunity for abortion, and not wanting or not having the opportunity for marrying or living together. Financial problems or other social circumstances often play a role. Especially in the US, teenage single mothers have become a serious social issue (see also teenage pregnancy).
This phenomenon has become one of the serious social issues in advanced countries. A single father is less common because many single parenthoods are caused by pregnancies after which the father deserted the mother, and because after divorce, more often the woman gets custody of the children, and in the case the mother has no (longer) a relationship with the father, it is even more likely that the child will stay with the mother; the father may even be out of view. A single father is considered much less commonly a social issue and gets far less support from governments. The typical case of a man turning into a single father probably entails that his wife died or disappeared in other ways.
Sometimes, when a woman is pregnant, she and the father of the child feel the need to marry, or to marry earlier than planned, to avoid the shame and the legal complications of being a single mother. This is sometimes referred to as a "forced marriage". It has become more common in Japan and the United States because couples over there usually feel they have little reason to get married.