Attraction or Nonattraction to Relatives: Biological or Psychological?

Question

After reading the question from the guy in India who wants to marry his first cousin, I started thinking about why I have no sexual desire for any of my female relatives.

I have a niece and a first cousin who are in their late teens. They're both hot, but my cousin is Miss America quality.
She's prettier than most girls I've ever dated, but I don't have fantasies of her and I in bed. When I was a little kid, I had a crush on a 12 years older girl relative whose great grandmother and my great grandmother were first cousins. That means we don't share enough of the same DNA to cause potential birth defects.

My question: Is there a biological sense that keeps us from being attracted to relatives who share too many of the same DNA in order to prevent birth defects? Most animals, humans included, usually resort to incest if there's not much choice in mates. Therefore, risky birth is better than no offspring at all
OR, are we just drilled from birth into believing it's wrong?

Answer 1

It can't be biological because people in other countries marry relatives and it is a social custom. The social custom in this country has been to avoid relatives up to third cousins. The reason for this may be, first, this country is very diverse and it became uncustomary in its early days to have relatives living close by. Another reason is that many of our forefathers saw a problem with familial intermarriage, namely, an increase in children born with genetic defects because relatives with a recessive gene have a greater chance of producing offspring with both genes or the combination of genes. Around this time laws of genetics were becoming more well known, which proliferated good information and bad information. There may have been other reasons.

Answer 2

Just because you do not feel this attraction toward your relatives does not mean others do not toward their relatives, thereby throwing the theory of whether we are predestined by DNA not to feel this sort of attraction.

In my opinion it all boils down to the very elusive thing called 'chemistry', which I believe to be very real. If it is there, relative or not, it causes a mighty strong pull.

As an added note, I had three second-cousins who I used to race matchbox cars with when I was a little girl. When I was about twenty-four, the youngest , then maybe twenty-two told me that he had always had feelings for me. He was just drop-dead gorgeous at that age and my awful confession is that we did kiss - a lot. It didn't go any further because I wouldn't let it, but him being a cousin did not stop the fact that there was an attraction.

If men, by nature or other, could rule over who and what we were attracted to, imagine how many less heartaches, wars, crimes, there would be.

Finally, we are not drilled from birth about this as it is something that really doesn't arise in conversation or other until way down the road (way past the diaper stage at least).

Answer 3

Nature vs. nurture? I would say that it's mostly nurturing. If you never met or knew your niece or cousin, would you still not be attracted to them? You just said that they were both hot, so I'm guessing you wouldn't feel the same way. Or let's say you were raised in a culture where incest was acceptable, would you still feel the same way?

Answer 4

Psychological. Who you are attracted to is determined by cultural factors. Biological processes are just the result of the initial attraction. For example: Gay men who act highly effeminate identified with the mother instead of the father, and are therefore attracted to men, they are still biologically male. The same goes for women who identified with the father and become attracted to women.

Answer 5

It's called the Westermark effect and it seems to depend on both nature and nurture. Specifically, if you grow up with someone from very early in life, then you're very unlikely to feel any sexual attraction to them.