a range of socioeconomic classes, but was particularly common among poor and rural families. Among the well to do, marrying a son in a major marriage was prestigious and a display of status, but also costly. In poorer and more rural communities, shim-pua minor marriage was inexpensive and helped to ensure that no matter how poor a family was, their sons would have wives when they reached marrying age, and thus a greater likelihood of producing descendants. In contrast, the high bride price to acquire a bride for a son to wed in a major marriage could be prohibitive, sometimes as much as a year's income for the family. If the family could not afford such a bride for major marriage, this could result in a failure to produce descendants and the end of the family lineage. In contrast, the costs of adopting an infant daughter were low and the costs of raising her as a shim-pua often included only food and clothing. In poor communities, limited wealth or status motivated both the adoption of a shim-pua daughter into the family and the giving up of biological daughters as shim-pua to other families. For a family of limited means or social status, a biological daughter offered little surety; traditionally she would be married off into another family and would neither care for her parents in old age nor extend the family lineage. In contrast, a shim-pua daughter would remain in the household, caring for the parents through their old age, and would bear their descendants. For these reasons, adoption of an infant shim-pua daughter frequently coincided with giving up a biological infant daughter for adoption and then raising the shim-pua daughter in her place. These marriages were often unsuccessful. This has been explained as a demonstration of the Westermarck effect. End of the practice In mainland China, the practice was outlawed by the Communist Party of China in 1949. In Taiwan, several legal issues arose in the 1950s, when shim-pua daughters were registered as adopted daughters, or their male equivalent were registered as adopted sons. Because the couple were legally considered step-siblings, the Taiwanese common law forbade their marriage. Three judicial reviews were made by the Judicial Yuan to allow their marriage. Shim-pua marriage fell out of practice by the 1970s due to increased wealth resulting from Taiwan's economic success, making such arrangements unnecessary. One factor that accelerated the demise