Jess pointed out
, there seems to be a dearth of medical literature on "genetic sexual attraction"-I checked out one database and found very little on humans though there was some stuff on songbirds and mice. Which is odd, given that the ever-changing makeup of families today would suggest that it's worth study. Maybe feeling attracted to somebody you're genetically related to is a legitimate syndrome, or maybe it's just a ready-made excuse for own-child molesters to justify their actions. I have to say, the skeptic in me inclines toward the latter. Then again, it's plausible that biological siblings, raised apart and meeting as adults, would feel overcome by a disorienting tangle of emotions that might include attraction. The same, I guess, could apply to a biological parent and the child given up for adoption, as in the case of Aimee Sword.
I'm surprised that so little has been written about it because the topic does come up when professionals talk about adoption and the issues it raises. Several years ago, researching a book on reproductive technology, I heard GSA mentioned at conferences, typically in discussions about whether adoptees should meet their birth parents (and siblings) and what can happen when they do. I think the argument for why GSA might exist runs this way: When biological siblings are raised in separate households, the incest taboo doesn't have a chance to develop. And at least some research has shown that like attracts like, so when they meet as adults, there is nothing to mitigate that attraction. Ditto for kids raised apart from their biological parents. Even if it's legit, though, it would seem that most people successfully resist those feelings, so Aimee Sword, whose lawyer says she " can't understand " her appalling behavior, has no excuse. And her biological son, the victim in all this, was no consenting adult.
Jess is right, though, that we may be hearing more of this in the future-not only because people like Sword may use social networking to track down or stay in touch with biological offspring who were adopted. It's also a concern in the explosively growing sperm- and egg-donation industry, which is so little regulated in this country that the same sperm donor may be responsible for scores of births. I interviewed a woman who, pregnant with sperm-donor twins, happened to meet a woman who lived across the street from her who was also pregnant with sperm-donor twins. Chatting, the two discovered that they had used the same donor. Which was less surprising than you might think: Both women were Jewish; both worked in the same field; both shopped at the same local sperm bank; both tended, given their similar interests, to gravitate toward the same donor pool. As they worked their way through the implications, they realized that their four kids, half-siblings, would attend the same school. What if the two women hadn't met or compared notes? What friendships might have developed among their children? Is it any surprise that one of the moms eventually took her kiddies and moved far, far away? Given that this seeming coincidence does, in fact, happen, it might behoove the therapeutic community to study genetic sexual attraction and whether it exists. Parents of sperm- and egg-donor offspring do worry that their kids might meet and marry relatives, in the course of random dating; if GSA increases the likelihood, they'd doubtless like to know that, as well.
If GSA does exist, it seems to operate mostly among people who are related but did not grow up together. Which also raises the question: How does the incest taboo-or whatever mechanism prevents siblings raised together from feeling attracted to one another-work? The Freudian line of reasoning, I think, would hold that young children do feel incestuous urges, and that part of human development is getting over this. Evolutionary biologists might argue that liaisons between those who are genetically related produce weak offspring, so we are disinclined toward them. (The literature I scanned on the animal kingdom suggested that scent may be one way to detect genetic relation and avoid inbreeding.) The Greeks saw all of this as a rich engine of tragedy, if nothing else. Interestingly, the same Guardian article that Jess references points out the work of Finnish anthropologist Edward Westermarck, who theorized that there is a natural aversion-not a natural attraction-between kids raised in proximity, which develops as a result of "overfamiliarity and boredom." The article talks about studies done in kibbutzes in Israel, which found that those kids, unrelated but raised in the closest intimacy, were, as adults, strikingly disinclined to marry or have sex with one another. So it does seem to be familiarity that breeds, if not contempt, then unattraction. And guess it could work the opposite way for siblings raised apart.
Then again, I suspect that a great number of genetic relatives, meeting for the first time, are overwhelmed by feelings of ... neutrality, puzzlement, and the sense of: How could I possibly be related to this stranger? Which is also a common feeling in families, even among people raised together.
Photograph of mother and son at the beach by Stockbyte.