Like many folks, I first heard of human chimeras listening to an NPR segment last summer. I’ve read numerous articles (including the ones linked on the NPR site) on the subject and it has been a favorite subject of discussion with my coworkers - IANAGenetic Expert/Lawyer/Doctor/Theology-Dude/Philosopher, and for the most part neither are my coworkers and friends.
What I’d like to know is what you SDMB Genetic Experts/Lawyers/Doctors/Theology-Dudes/Philosophers think are the most significant issues having to do with the existence of human chimeras, the unknown number of them in the population, and particularly the possibility (though remote, as far as I understand) of a human chimera with two or more distinct sets of contributing parents (mothers AND fathers). For instance, could a human chimera have entirely unrelated components (a GQ question, I know), and what are the legal, moral, etc. consequences of their hypothetical existence?
And then, would it be genetically not-wrong for the completely hermaphroditic, parentally distinct human chimera to impregnate him/herself?
I apologize if this is an extremely ignorant question; chalk it up to my first thread. I’ve been searching the SD and SDMB archives for several weeks and have only seen oblique references to threads about human chimeras, many without non-external links.
The only legal issues I could foresee would be in deciding parenthood, which usually involves a DNA test these days. Such a test should show something like this, and a scientific oddity can be dealt with on a case by case basis from that point. It would seem to me that if a child had multiple fathers (I don’t see how you’d get multiple mothers outside of a lab) the gene-based rights of each father would be equal, and other grounds would decide the case.
Morally/ethically, your genes aren’t a moral or ethical issue. So it’s no more an issue than the existence of any other genetically definable group, like a race or gender.
Self impregnation is out there. I would say the issues are the same for procreative incest, in that even though consent is there there’s a danger to the offspring. If you actually had two completely seperate set of genes for each gender, I assume that’s out of the picture, but you’re still talking about a kid whose in for one screwed up explanation of where he/she came from.
Chimeras between two entirely different animal species have been created in the lab, so I see no reason why a chimera from two fertilized human eggs (each from a seperate set of parents) couldn’t occur as well.
Why would there be any legal issues? The chimera is a person like anyone else.
I guess by legal issues perhaps I meant criminal law issues - the NPR bit as I recall discussed the effects of the existence of human chimeras in the context of DNA testing of evidence.
Certainly their existence does not mean that innocent suspects will be wrongfully convicted . . . however what if a cell from a fraternal twin (that still developed into an independent fetus) fused with a fertilized egg and one twin’s DNA showed up in evidence left at the crime scene (Possible? Again IANAGE). In addition to DNA evidence, prosecutors in the future might also establish that the accused is not a fraternal twin, and/or that her fraternal twin is not a human chimera. I guess that’s what I was thinking about.
OK. Interesting point. But first, there isn’t any “fraternal twin” to know about for true chimeras-- ie, the fusing of two fertilized eggs. And most fraternal twins don’t make it to birth, so you’d still have a limitted sample of known fraternal twins to work from. Maybe forensic scientists will have to take several different tissue samples to test if they want to determine if the person is or isn’t the criminal. Messy, but not a problem that needs some tricky technical solution.