Poverty is often a root cause of child abandonment. Persons in cultures with poor social welfare systems who are not financially capable of taking care of a child are more likely to abandon him/her. Political conditions, such as difficulty in adoption proceedings, may also contribute to child abandonment, as can the lack of institutions, such as orphanages, to take in children whom their parents can not support. Societies with strong social structures and liberal adoption laws tend to have lower rates of child abandonment.
Historically, many cultures practice abandonment of infants, called "exposure." Although such children would survive if taken up by others, exposure is often considered a form of infanticide -- as described by Tertullian in his Apology: "it is certainly the more cruel way to kill. . . by exposure to cold and hunger and dogs". This form of child abandonment is much more widely spread throughout societies, being used even by the rich to dispose of unwanted children, particularly girls. Many of these children were indeed taken up for slavery and prostitution.
Early laws governing child abandonment often prescribed that the person who had taken up the child, either to adopt or to raise as a slave, was entitled to the child. This both discourages the practice of exposure and encourages strangers to take up exposed children.
Today, abandonment of a child is considered to be a serious crime in many jurisdictions because it can be considered malum in se (wrong in itself) and due to welfare concerns. For example, in the U.S. state of Georgia, it is a misdemeanor to willfully and voluntarily abandon a child, and a felony to abandon one's child and leave the state. In 1981, Georgia's treatment of abandonment as a felony when the defendant leaves the state was upheld as constitutional by the U.S. Supreme Court.
Foundlings, who may be orphans, can combine many advantages to a plot: mysterious antecedents, leading to plots to discover them; high birth and lowly upbringing. Foundlings have appeared in literature in some of the oldest known tales. The most common reasons for abandoning children in literature are oracles that the child will cause harm; the mother's desire to conceal her illegitimate child, often after rape by a god; or spite on the part of people other than the parents, such as sisters and mothers-in-law in such fairy tales as The Dancing Water, the Singing Apple, and the Speaking Bird. Poverty usually features as a cause only with the case of older children, who can survive on their own. Indeed, most such individuals are of royal or noble birth; their abandonment means they grow up in ignorance of their true social status.
One of the earliest surviving examples of child abandonment in popular culture is that of Oedipus who is left to die as a baby in the hills by a herdsman ordered to kill the baby, but is found and grows up to unwittingly marry his biological mother.
In many tales, such as Snow White, the child is actually abandoned by a servant who had been given orders to put the child to death.
Children are often abandoned with birth tokens, which act as plot devices to ensure that the child can be identified. In Shakespeare's The Winter's Tale, a recognition scene in the final act reveals by these that Perdita is a king's daughter rather than a shepherdess, and so suitable for her prince lover. Similarly, when the heroine of Le Fresne reveals the brocade and the ring she was abandoned with, her mother and sister recognize her; this makes her a suitable bride for the man whose mistress she had been.
From Oedipus onward, Greek and Roman tales are filled with exposed children who escaped death to be reunited with their families -- usually, as in Longus's Daphnis and Chloe, more happily than in Oedipus's case. Grown children, having been taken up by strangers, were usually recognized by tokens that had been left with the exposed baby: in Euripides's Ion, Creüsa is about to kill Ion, believing him to be her husband's illegitimate child, when a priestess reveals the birth-tokens that show that Ion is her own, abandoned infant.
This may reflect the widespread practice of child abandonment in their cultures. On the other hand, the motif is continued through literature where the practice is not widespread. William Shakespeare used the abandonment and discovery of Perdita in The Winter's Tale, and Edmund Spenser reveals in the last Canto of Book 6 of The Faerie Queen that the character Pastorella, raised by shepherds, is in fact of noble birth. Henry Fielding, in one of the first novels, recounted The History of Tom Jones, a Foundling. Ruth Benedict, in studying the Zuni, found that the practice of child abandonment was unknown, but featured heavily in their folktales.
The strangers who take up the child are often shepherds or other herdsmen. This befell not only Oedipus, but also Cyrus II of Persia, Amphion and Zethus and several of the characters listed above. Romulus and Remus were suckled by a wolf in the wilderness, but afterward, again found by a shepherd. This ties this motif in with the genre of the pastoral. This can imply or outright state that the child benefits by this pure upbringing by unspoiled people, as opposed to the corruption that surrounded his birth family.
Often, the child is aided by animals before being found; Artemis sent a bear to nurse the abandoned Atalanta, and Paris was also nursed by a bear before being found. In some cases, the child is depicted as being raised by animals; however, in actuality, feral children are incapable of speech.
Moses is unusual in that he is taken up by a princess, who is of superior birth to his mother, but like the other foundlings listed above, he reaches adulthood and returns to his birth family. This is the usual pattern in such stories.
The opposite pattern, of a child remaining with its adoptive parents, is less common but occurs. In the Indian epic Mahabharata, Karna is never reconciled with his mother, and dies in battle with her legitimate son. In the Grimm fairy tale Foundling-Bird, Foundling Bird never learns of, let alone reunites with, his parents. George Eliot depicted the abandonment of the character Eppie in Silas Marner; despite learning her true father at the end of the book, she refuses to leave Silas Marner who raised her.
When older children are abandoned in fairy tales, while poverty may be cited as a cause, as in Hop o' My Thumb, the most common effect is when poverty is combined with a stepmother's malice, as in Hansel and Gretel (or sometimes, a mother's malice). The stepmother's wishes may be the sole cause, as in Father Frost. In these stories, the children seldom find adoptive parents, but malicious monsters, such as ogres and witches; outwitting them, they find treasure enough to solve their poverty. The stepmother may die coincidentally, or be driven out by the father when he hears, so that the reunited family can live happily in her absence.
In a grimmer variation, the tale Babes in the Wood features a wicked uncle in the role of the wicked stepmother, who gives order for the children to be killed. However, although the servants scruple to obey him, and the children are abandoned in the woods, the tale ends tragically: the children die, and their bodies are covered with leaves by robins.
When the cause of the abandonment is a prophecy, the abandonment is usually instrumental in causing the prophecy to be fulfilled. Besides Oedipus, Greek legends also included Telephus, who was prophesied to kill his uncle; his ignorance of his parentage, stemming from his abandonment, caused his uncle to jeer at him and him to kill the uncle in anger.
Foundlings still appear in modern literature. In G. B. Shaw's stage-play 'Major Barbara', industrialist Mr. Upshaft (a foundling himself), intently searches for a foundling to assume the family business. Superman may be seen as a continuation of the foundling tradition, the lone survivor of an advanced civilization who is found and raised by Kansas farmers in a pastoral setting, and later discovers his alien origins and uses his powers for good. Elora Danan, in the film Willow, and Lir, in the novel The Last Unicorn, both continue the tradition of foundlings abandoned because of prophecies, and who fulfill the prophecies because of their abandonment. In the last book of The Chronicles of Prydain, Dallben reveals to the hero Taran that he is a foundling; in a story set in the same world, "The Foundling", Dallben himself proves to be also a foundling.