In discussing incest it would be well to start on common ground. These web sites provide information that might help in that regard:
1. Sexual relations between persons who are so closely related that their marriage is illegal or forbidden by custom.
2. The statutory crime of sexual relations with such a near relative.
Wikipedia has this to say:
Incest is sexual intercourse between close relatives that is usually illegal in the jurisdiction where it takes place and/or is conventionally considered a taboo. The term may apply to sexual activities between: individuals of close "blood relationship"; members of the same household; step relatives related by adoption or marriage; and members of the same clan or lineage. See also Laws regarding incest.
Consensual adult incest is seen by some as a victimless crime. However, children born of incestuous unions have greatly increased risk of death and disability at least in part due to genetic diseases caused by the inbreeding.
Although it is illegal or partially prohibited in most countries, Russia, China, the Netherlands, Spain, France, Turkey, Israel and the Ivory Coast have no legal prohibitions on consensual incest between adults, and Switzerland has considered legalizing it.
The following are questions that interest me but no doubt there are others that some of you may think more important (they are questions, they are neither factual statements, rules nor opinions):
*How frequent is incest?
*Is incest more frequent now or in the past? Why or why not?
*Who are the parties involved?
*Why does it occur?
*Can it be prevented? How?
*Should it be condoned or made legal between consenting adults?
*If it can't be totally eliminated can the incidence of it be reduced? How?
*Are there controllable factors that contribute to incest?