Extra embryos are an frequent and generally unavoidable consequence of IVF. This means that figuring out what to do with those extra embryos is a fairly common dilemma for those engaged in IVF. This is reflected in a couple of stories I’ve seen on the web recently. While sometimes the focus is just on the practice of “embryo adoption” I’d like to think more broadly about the topic for a moment.
First off, consider why the extra embryo problem arises and why it will not go away anytime soon. The best practice now is probably to transfer just a single embryo (or at most two) into the uterus of the woman who will be pregnant. This vastly reduces the chances of multiple births, which are problematic for a number of reasons.
But even if you know you will only transfer one embryo you very likely begin by creating more than one. There are at least a couple of reasons for this. First off, you almost always start with more than one egg. Given the process used to harvest the eggs, people who are providing them generally use fertility drugs which makes them hyperovulate and that means you start with a batch of eggs.
So you have multiple eggs. It is possible to freeze and later thaw the eggs, but this is a relatively new deal and probably not common yet. It’s much easier to freeze embryos. And you may very well need more than one embryo even if you only transfer one at a time as the first attempt at IVF may not work.
Further, you actually want a few embryos to choose from. Not all embryos created (by IVF or otherwise) are actually viable–not all have the capacity to develop into a child. Using PGD it’s possible to eliminate embryos that have no chance of developing properly. (I realize that the whole PGD process raises tons of questions around eugenics I’ve touched on some of them elsewhere.)
With all this in mind it seems to me highly likely that you will create at least a few embryos with the idea of using one and freezing the rest. (I have no idea what the average number of embryos created is but it might be interesting to see if it is available somewhere. Suffice it to say I’m sure it is more than one and would bet a lot it’s closer to six.)
This brings me back to the stories I linked to. The one from SMH (which I think is the Sydney Morning Herald) notes that it is thought that there are more than 100,000 frozen embryos in Australia. That’s a very large number if you think about it, and Australia is hardly the most populous nation where IVF is used. (The population of Australia is a bit less than the population of Texas.) What is to become of all the frozen embryos? It sounds like for the moment they are mostly just sitting in the freezers.
The question of disposition is hard in part because we don’t have a good category for frozen embryos. They aren’t people (I know some will disagree with that, but I’m starting there. If you do think they are people this might be easier.) But many people also feel that they aren’t simple property, like a table or a chair.
It’s pretty clear that the people who have to decide what to do with them are the people for whom they were created–and that’s true whether those are the people whose gametes were used or not. Presumably these people will already have a child who is a full genetic sibling of any child that might result from use of the frozen embryos. That makes the proposition rather more complicated, psychologically speaking. (Legally I think it is fairly clear that you can just give the embryos to whoever you want. It’s not an adoption question.)
People using IVF are generally overwhelmed by all the unknowns and uncontrollables that are a part of the process. I wonder if it’s really possible to focus on the question of the potential left-overs in advance. I wonder too if it’s possible to know what you’ll think at that point. But clearly this is an issue that will be with us for a while and will only grow larger. It’s a topic that Naomi Cahn and June Carbone (both insightful academics) are working on, too. Timely stuff that’s worth reading.