Locksmith Patrick Stübing and Susan Karolewski are a German couple with four children. They are also full biological siblings. “Eeeeewww”, I hear you say. And I agree. Eeeeewww. But why do we feel that way?
The incest taboo is as close to a cultural universal as you can get, and is most likely genetically determined. It is counteradaptive to want to bonk your siblings, as this may lead to the accumulation of harmful recessive alleles in the offspring. But how is this implemented from a practical evolutionary perspective? Humans have no physical way of identifying their biological siblings, usually relying for this information on whatever mom & dad tell them. Instead, it appears that humans are built in such a way that they don’t generally want to bonk people of the same age with whom they have grown up in close contact (the “Westermarck effect“). Historically, this would have kept our ancestors from mating with siblings, cousins and younger aunts/uncles.
Stübing was placed in an orphanage at age four. Three years later, Karolewski was born. When he was 23 and she was 16 the two met for the first time. This means that their anti-incest biological programming never had any opportunity to do its thing. They became a couple, got a home of their own and had four children. So far, so good.
But three of those children have been taken into foster care. And Stübing has received several jail sentences due to a German law from 1871 prohibiting sex between siblings. (I don’t know why Karolewski hasn’t.) Says the federal Constitutional Court in a recent ruling, intercourse between grown-up siblings jeopardises “the family’s vital function in society”. The ruling also refers to the “health of the population”.
This ruling is bad and wrong in so many ways. To be able to discuss this in principle, let’s assume (as appears likely) that all sexual contact between the couple has been consensual and that their children were not taken into custody for any other reason than their parents’ close biological relationship.
- This is a victimless crime.
- The couple’s children have become the victims of unnecessary state intervention.
- People with genetic defects are free to procreate provided only that they are not close relatives, cf. Tay-Sachs and similar effects of religio-ethnic isolation.
- The idea that the state should monitor the genetic makeup of the population is a holdover of long-discredited eugenic pseudoscience, which Germany has particular historical reason to distance itself from.
- Even if the Stübing-Karolewski children do accumulate genetic defects, then this is a temporary problem lasting only one generation, as they are unlikely to repeat their parents’ procreative stunt.
The whole affair is deeply controversial in Germany, and I’m happy to note that the vice president of the Constitutional Court, Winfried Hassemer, has reserved himself against the ruling in very strong language.
All western countries have legislation to protect children from sexual abuse by teens and adults, all western countries outlaw rape, regardless of biological relationships. And for evolutionary and cultural reasons, the great majority of all people on Earth aren’t remotely interested in bonking their siblings. Adults around the planet are constantly engaging in all manner of consensual sexual intercourse that might make me go “eeeeewww”, but none of them has asked me what I think. It’s none of my business. Besides, looking at Stübing and Karolewski, I would never have guessed that they are related, thus obviating any queasy feelings. To tell the truth, I find all of my six female cousins pretty hot, though we’ve never been that friendly. And my kids are just about as far from inbred as it is possible to be.
In Sweden, I am sad to say, sex between siblings is also a crime, punishable by up to a year in jail. This kind of legislation is outdated and should be overturned. Stübing and Karolewski are trying to use their case to make that happen in Germany.