What is Incest?
[[File:Jan Massys-Loth et ses filles IMG 1419.JPG|thumb|Lot and his daughters, by [[Jan Massys]], 16th century]] [[File:Charles II of Spain.jpg|thumb|[[Charles II of Spain]], portrait, as a child, avbout 1666, by [[Juan Carreño de Miranda]]. Charles only learned to speak at age four, and started to walk at age eight. As a result of incest, he was likely handicapped. He was the last [[House of Habsburg|Habsburg]] on the Spanish throne.]] '''Incest''' means [[sexual intercourse]] between people who are closely [[wikt:relation|related]]. Usually, this means members of the same family. In many societies, it is [[wikt:forbidden|forbidden]] by [[law]] and [[religion]]. Which relatives it is forbidden to have sex with depends on the law, religion and culture. Incest is now regarded as bad for the [[Genetics|genetic]] health of the offspring, and it is often forbidden by present-day religions and laws.<ref>Levesque, Roger J.R. 1999. ''Sexual abuse of children: a human rights perspective''. Indiana University Press. pp. 1, 5–6, 176–180. ISBN 9780253334718</ref><ref>United Nations Convention on the Rights of the Child. 1989. Office of the United Nations High Commissioner for Human Rights.</ref> The fundamental reason has to do with [[genetics]]. Incestual societies will have a high rate of [[birth defect]]s, significant enough for it to be noticed even when little was known about the cause. To some extent this is a surmise, because ancient societies had no knowledge of genetics as such. But they must have noticed some connection between birth defects and the relationship between parents. We think this because widespread bans on closely related persons marrying came long before the understanding of modern genetics. In history (as far as we know it) there were societies which allowed incestual marriages and individual acts of incest. Famously, the [[ancient Egyptian]] royal family practised incest, though not exclusively. It is thought that the frequency of early non-trauma deaths (such as [[Tutankhamun]]) was due to the e