Science Fiction and Sex: Incest

Since I began this primer on sex in science fiction, I keep going back to a conversation I had with a friend of mine. It happened unexpectedly when I was walking home from work late at night. The conversation lasted less than 5 minutes and it was among the most bizarre conversations I have had. Life always seems to happen when we are preoccupied, doesn't it? I find it a little irritating that so many important conversations take place outside, in the cold, underneath a street light. We talked about the taboo of incest, why we feel so immediately disturbed by it, if it is just a culturally built thing. You may have noticed in one of my other posts that, to me, the taboo of incest is just an evolutionary trait that keeps the gene pool sufficiently mixed and viable. Here was his premise:

Suppose a brother and sister, both adults, have a very close relationship. They decide they would like to have sex to deepen their relationship. They use contraceptives so that she will not become pregnant. No one else knows about it. No one is hurt by it. And there is no offspring. Is it wrong?

If you are like me, your mind screams that of course it is wrong. But why? I have stated my claim of evolution and yet I know it is wrong. Incest happens all the time, in many species. Definitions of incest vary from culture to culture, with some societies considering taboo what other societies accept as normative. Levi-Strauss suggested that the discouragement of incest was a social force. Marriage and offspring form strong bonds and social networks. Forming such alliances strengthens communities by linking up several members of families. A marriage is not just between two people but also their families, the in-laws they join.

Think of times when incest was common. European and Egyptian royalty come to my mind. Marriage between close relatives, even half-siblings was common. Such close marriages keep material wealth and power concentrated. A pharaoh and his half sister need not worry about an interloper or concubine staking her claim since the half sister is the first wife, through whom inheritance is determined. In a situation where one person has multiple spouses, the sibling-spouse may be merely a figure of power and not a source of reproduction.

For reasons beyond my comprehension, many sci-fi books set in the future involve the political intrigue of feudal lords and ruling classes. With such concern over power and wealth, marriage is often a dangerous game. It threatens the stability of the family as well as the government. In other cases, alien species may reproduce in a manner different from our which renders concepts such as siblings, family and incest null. While the narrator or a character may seek to justify this, do not be misled - the author includes this element to make you uncomfortable, to make you distrust and dislike certain characters, and to make you put a wall between yourself and the incestuous persons.