A little PSAN (Public Service Announcement of Niftiness):
We talked a little in class last week about chimeras - not the Greek monster, though that would merit a PSAN as well, but creatures that manage to get more than one strand of DNA in their cells. It can happen in non-human animals (as seen with this fine "shoat" (I obey the disclaimer)), which produces some neat fur patterns and such.
But apparently it can also happen with humans. There are boring examples, based on things like blood transfusion or organ donation, when we just put someone else's DNA right into you. But niftier are the tetragametic chimeras. "Four gametes" - sort of gives it away. If, say, two fertilized eggs decide to merge, the adult human ends up with two sets of DNA, which may be distributed unevenly throughout the body. Your liver and heart, for example, may look like they come from different people. Or you can get two different colored eyes. Or Blaschko's lines, which I think look a lot like racing stripes. Zoom! Theoretically your two halves couldn't be that different from each other - you can only be as far apart genetically as two siblings could be, at the very most. (People sometimes like to say that chimeras are their own twin.) I imagine you're also limited by immunological issues - no embryo is going to make it too far if its two DNA lines view the other one as a foreign invader and attack it.
So that is neat for biological reasons. Nerds rejoice. But there's some nice potential for legal fallout as well. Take the case of Lydia Fairchild, an unknown tetragametic chimera who was told by social workers that she wasn't the mother of her own children - their DNA didn't match. Since "DNA is 100 percent foolproof and it doesn't lie," Fairchild actually was in the process of losing custody of her children before someone figured it out. I wonder if there's any potential for chimeric criminals out there, though that does seem like something of a comic book supervillian power. Quadruple Helix, they'd call him.
So just more evidence that human development is surprisingly durable - so many things can go wrong, and do, but somehow all of us are here. Amazing.
Tuesday, August 19, 2008
Monday, August 11, 2008
In honor of tomorrow's embryology exam, I thought I'd post a recent Bill Saletan article about (surprise!) abortion.
For those unwilling to click-and-skim, the basic gist is that a new Department of Health and Human Services regulation is aiming to "protect the right of employees to refuse to facilitate any abortifacient chemical or activity", where abortion is essentially defined as the expulsion of a fertilized egg. No doubt the aim of the regulation is to protect employees with who wanted to flex their conscientious objection muscles by refusing participation in anything from second term abortion down to the provision of emergency contraception ("Plan B", as Duramed Pharmaceuticals would have you view as a synonym).
Saletan points out, however, that lots of everyday activities would be abortion-enabling, by this definition; breastfeeding, exercise, and caffeine consumption have all been shown to hinder implantation of a fertilized egg. It seems incredibly unlikely that employees refusing to serve coffee will be protected under this new regulation.
This illustrates a larger trend I often see - the frequent lack of consistency that peppers pro-life rhetoric and pro-life policy. Plan B is a great example. If you look through the literature on the mechanism of emergency contraception, you basically find that it's not exactly clear how it works to prevent pregnancy. It's probably a three pronged attack: prevent ovulation, prevent fertilization, and/or prevent implantation. The last prong is what gets the conscientious objectors going - if you believe a fertilized egg is a human being, in some core sense (like Gomez-Lobo), you view obstacles to implantation as thwarting a human being's life.
Fine. Let that belief stand for the time being. The thing is that Plan B is essentially nothing more than a double dose of traditional oral contraceptives - you know, the kind that 12 million US women use daily. The Pill also works, most likely, with the same three pronged attack, blocking ovulation, fertilization, or implantation. It's likely that it works primarily by stopping ovulation, but recent studies show that's true of Plan B, too. They're basically the same chemical, after all. Both have a small but statistically possible chance of stopping pregnancy by preventing implantation.
But rarely do you have the same strong stand for pharmacists who don't provide the Pill that you do for those who refuse Plan B. (Put aside those communities who don't hang with any form of contraception at all.) And that doesn't really make sense. Your stance on the Pill and Plan B really have to hang together, since they're essentially doing the same biological thing.
It seems that pro-life regulations are essentially focused on the intent of the abortifacient - in these folks' minds, Plan B is meant to pull the rug out from a pregnancy, whereas the Pill is meant to stop one in the first place. Things like coffee drinking, breastfeeding, and exercise are even further from the realm of reproduction. But if you really and truly believe that that little one-celled thing is a human, you shouldn't care about intent. We certainly don't view soldiers killed by friendly fire as any less dead than those killed by the enemy, right? The fact that no one is crusading for the rights of embryos destroyed by caffeine (or hey, campaigning for research to end the miscarriages that end the lives so many embryos) always makes me suspicious of the motivations driving so many pro-life regulations.
For those unwilling to click-and-skim, the basic gist is that a new Department of Health and Human Services regulation is aiming to "protect the right of employees to refuse to facilitate any abortifacient chemical or activity", where abortion is essentially defined as the expulsion of a fertilized egg. No doubt the aim of the regulation is to protect employees with who wanted to flex their conscientious objection muscles by refusing participation in anything from second term abortion down to the provision of emergency contraception ("Plan B", as Duramed Pharmaceuticals would have you view as a synonym).
Saletan points out, however, that lots of everyday activities would be abortion-enabling, by this definition; breastfeeding, exercise, and caffeine consumption have all been shown to hinder implantation of a fertilized egg. It seems incredibly unlikely that employees refusing to serve coffee will be protected under this new regulation.
This illustrates a larger trend I often see - the frequent lack of consistency that peppers pro-life rhetoric and pro-life policy. Plan B is a great example. If you look through the literature on the mechanism of emergency contraception, you basically find that it's not exactly clear how it works to prevent pregnancy. It's probably a three pronged attack: prevent ovulation, prevent fertilization, and/or prevent implantation. The last prong is what gets the conscientious objectors going - if you believe a fertilized egg is a human being, in some core sense (like Gomez-Lobo), you view obstacles to implantation as thwarting a human being's life.
Fine. Let that belief stand for the time being. The thing is that Plan B is essentially nothing more than a double dose of traditional oral contraceptives - you know, the kind that 12 million US women use daily. The Pill also works, most likely, with the same three pronged attack, blocking ovulation, fertilization, or implantation. It's likely that it works primarily by stopping ovulation, but recent studies show that's true of Plan B, too. They're basically the same chemical, after all. Both have a small but statistically possible chance of stopping pregnancy by preventing implantation.
But rarely do you have the same strong stand for pharmacists who don't provide the Pill that you do for those who refuse Plan B. (Put aside those communities who don't hang with any form of contraception at all.) And that doesn't really make sense. Your stance on the Pill and Plan B really have to hang together, since they're essentially doing the same biological thing.
It seems that pro-life regulations are essentially focused on the intent of the abortifacient - in these folks' minds, Plan B is meant to pull the rug out from a pregnancy, whereas the Pill is meant to stop one in the first place. Things like coffee drinking, breastfeeding, and exercise are even further from the realm of reproduction. But if you really and truly believe that that little one-celled thing is a human, you shouldn't care about intent. We certainly don't view soldiers killed by friendly fire as any less dead than those killed by the enemy, right? The fact that no one is crusading for the rights of embryos destroyed by caffeine (or hey, campaigning for research to end the miscarriages that end the lives so many embryos) always makes me suspicious of the motivations driving so many pro-life regulations.
Sunday, August 10, 2008
Two weeks ago, my brother mentioned to me, ever so pointedly, that what he'd really like to see is a blog written by a female med student with a background in ethics. Funnily enough, I am the only such person he knows. So this blog is partly for him.
It is also partly for my own peace of mind; I'm a big fan of the world beyond school, and writing will hopefully spur me to look up from my anatomy textbook every so often and keep track of the bigger picture. I want to drag my heels as much as possible as they pull me into the insular little world of medical academia.
There might very well be a dearth of blogs from those inside the medical field (as opposed to those bloggers pontificating on health care policy from the outside) because, well, there's simply not enough time. It is not my goal to blog about the process of failing out of med school, you see. I would give this blog a 50-55% chance of survival (note clever medical terminology!). But that's the beauty of blogspot, I feel: a cheap, clean, and eminently disposal soapbox.
It is also partly for my own peace of mind; I'm a big fan of the world beyond school, and writing will hopefully spur me to look up from my anatomy textbook every so often and keep track of the bigger picture. I want to drag my heels as much as possible as they pull me into the insular little world of medical academia.
There might very well be a dearth of blogs from those inside the medical field (as opposed to those bloggers pontificating on health care policy from the outside) because, well, there's simply not enough time. It is not my goal to blog about the process of failing out of med school, you see. I would give this blog a 50-55% chance of survival (note clever medical terminology!). But that's the beauty of blogspot, I feel: a cheap, clean, and eminently disposal soapbox.
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