Originally Posted by Jeff the Green
In general, the studies look at twins separated at birth (something that has mercifully mostly stopped now), so none of them were breast fed.
Early childhood experiences can strongly affect sexuality in general. There is, for example, the famous Westermarck effect, which causes children to assume any other child they grew up with to be a sibling, and so not sexually attractive. This came to be a problem in the Kibbutzim of Israel, where children were raised communally, and so none were attracted enough to each other to marry! On the other hand, we tend to desire people who look similar but not identical to the primary caregiving adults in our young years, which is why many straight men/gay women end up with women who look vaguely like their mothers and gay men/straight women often end up with men that look like their fathers.
Yeah, I'm familiar with the what's-his-name effect, though I never remember the name, and the issues in the kibbutzim. But that has a very clear evolutionary benefit, whereas attraction to people similar to one's parents seems to me to be a potentially bad thing; if they share many traits, they might share many genes, so mating with them could be a bad thing. So I really don't understand how the attraction to people similar to one's parents thing worked out evolutionarily, I would have expected it to work out like the what's-his-name thing if I had been theorising this stuff while studying primates a few hundred thousand years back. Slight tangent now, looks likes.