Can THIS be true? Its really thought provoking on a number of levels. I haven't had time to listen to the original story, or look it up and find out about it, but Amanda's report over at Pandagon (and yes, I know she's a girl and stuff but still, science...cool!)
Here's a slice of the post, linked above:
So I just listened to a recent edition of Radio Lab about bioengineering and chimeras and the possibilities of blending genes, and in the show was this really amazingly cool story. Basically, this woman they interview needed a kidney transplant. (That’s not the cool part.) They go to family members first, of course, and they tested their DNA for a match. And they found that her sons…..were not her sons. They were her husband’s sons, but they weren’t a genetic match to her. So they retested her, same result. So they desperately tested a lot of different tissues around her body, after she demonstrated that she did in fact give birth to these boys, and they found out that the reason for all this was some of her body had one set of DNA and another had another. Her blood had one, but her reproductive system had another.
I felt bad for the lady. Obviously, this whole situation unnerved her and rattled her to the bone, and it’s too bad. I can’t help but think that if I found out that I’ve got the genetic material to make two people, I’d be stoked.* What great cocktail party banter! You could probably convince people you had superpowers and shit. I don’t truck with the more superstitious need to have individuality strongly defined in religious or biological terms—a person is a social construct that I think is best defined around the concept of the lived experience of having your consciousness and your body and your memories. But most people probably don’t think very much about the constructed nature of identity, and thus a revelation like this was pretty rattling. Most people think what you are is what you are, that your race and ethnicity and gender are set in stone and that your unique personhood is something special. But really, it’s not. Human beings are what we socially define them to be, and the boundaries can be blurred as the social understandings of these things are blurred.
And of course, the biology. For those who find these sort of oddities fascinating, you’ve probably already guessed what happened to this woman. When her mother was pregnant, she was initially pregnant with fraternal twins. At the embryonic stage, the two fused together, a process that often results in Siamese twins [A commenter pointed out this is not exactly accurate for all conjoined twins.--Aimai.] In this case, the twinning happened on the level of organs, with some being made by one set of DNA and some being made by the other set. Her sons were actually her sons, of course, but they were just made by one twin half of her body. We like to think of Siamese twins as being two sets of individuals fused together, but more often, that’s not what happens. If a Siamese twin body is like this, or one fetus is absorbed into the body of the other that was born, or if the twin is split from the waist down and has three legs instead of two heads, we understand that person as one person. Only if there are two unique brains—two unique consciousnesses, that is—do we understand that there are two people.