Dean Stretton imagines a case in which an emergency arises and a person is faced with the choice of rescuing ten frozen human embryos or five adult patients. Since virtually everyone would choose to save the adult patients rather than the embryos, this indicates that the patients have a higher moral status than the frozen human embryos. 
On the surface this seems to make sense. After all, the pro-life case is that from fertilization unborn human beings are morally equivalent to adults. You would think the ethical thing to do would be to rescue the greatest amount of humans possible, in this case the ten embryos. But if we would allow embryos to die in the fire by rescuing another human, how does that justify our intentionally killing them through abortion?
In Dean Stretton’s argument, the embryos in question were conceived through in vitro fertilization. That means we have no idea what’s going to happen to them. They may be implanted into a woman hoping to conceive (or several different women), or they may be used for research. This is tragic, but we simply don’t know the ultimate fate of these embryos. On top of that, even if they are scheduled for implantation, there’s no guarantee that all of them, or even any of them, will take. They may not implant. Therefore you would be morally justified in rescuing the adults, even over a greater number of human embryos.
Consider it like a case of triage. Two people are in mortal danger and a doctor can only save one. The doctor will save the person with the greatest chance of survival. Does that mean the other person is less valuable than the person she saves? Of course not. But if she tried to save the person with the most extensive injuries, she may end up losing both. In this case, since the fate of the embryos is uncertain (nor could it ever be certain), saving the adults would be morally justified because they have a 100% chance of survival if you rescue them.
But what if you modified Stretton’s argument to make it stronger? What if you knew for certain that all the embryos would be given to women, and technology has advanced to the point now that we can guarantee that all, or at least the vast majority, would implant?
I still would not change my answer. How would choosing to save one entity over another prove that the entities I didn’t save aren’t human (or are not human in a “morally relevant” sense)? In fact, we could change the conditions of the scenario. Say you’re in a burning building. In one room is your mother, and in another room is a complete stranger. You only have time to save one. I would almost guarantee you would save your mother. But does that mean the one you didn’t save wasn’t human? What if you were faced with the choice of rescuing your spouse or child or a room full of people? If you save your spouse or child over the roomful of people, that does not mean the people in the other room were not human.
Third, even if we were told ahead of time that these embryos were scheduled for implantation, we would still be morally justified in saving the adults. As Christopher Kaczor explains,
“…killing a regular person and killing the President of the United States are equally wrong as killing. The regular person and the President have equal rights to live. However, unlike killing a regular person, killing the President may also generate global instability, upset millions of people, and perhaps even prompt massive retaliation or world war. These factors make the assassination of any world leader more grievously wrong than killing a private citizen, but, nevertheless, killing the President and killing a private citizen are equally wrong with respect to the violation of the right of life…we have moral justification for treating human beings enjoying basic equal human rights in different ways. If forced to choose between saving the President of the United States and four other national Presidents and Prime Ministers, rather than ten unknown patients, most people would choose the Presidents and the Prime Ministers. To choose to save Presidents and Prime Ministers rather than plain persons is not a denial of the equal basic rights of those not saved, but rather a recognition that deaths of world leaders adversely affects many more people than the deaths of regular patients. Similarly, in virtue of the fact that the adult patients have received an ‘investment’ from their parents and society in terms of education and upbringing, have future plans that would be thwarted, have responsibilities to discharge, and have strong relations with others, it makes sense to choose to save five adult persons rather than ten frozen embryos. In choices about who to save, various circumstances can determine who is chosen without a denial of the fundamental equality of the human beings involved. The embryo rescue case does not show that human embryos lack basic human rights.” 
Pro-life philosopher Scott Klusendorf notes,
“…moral intuitions are important, but they are not infallible. We must examine them in light of reason. A little over a century ago, many whites thought it unthinkable that anyone would consider black slaves human beings…Thus, it’s no stretch to imagine a proponent of slavery putting the following challenge to a northern abolitionist: ‘Your barn is burning. You have the choice of saving a Negro slave or a white schoolboy. Which would you choose?’ If a majority of abolitionists leave a black kid behind, does that change the kind of thing he is…?”  In other words, is the black slave non-human even if a slavery abolitionist would leave him behind to save the white schoolboy?
This burning IVF facility scenario may seem like a silly situation but that’s the nature of thought experiments. The Stanford Encyclopedia of Philosophy defines a thought experiment as “devices of the imagination used to investigate the nature of things.” We can’t just dismiss a thought experiment because it’s “too weird.” We must engage with it intellectually.
That being said, the thought experiment doesn’t seem so bizarre when we consider the real-life example of Noah Benton Markham, a survivor of Hurricane Katrina that hit New Orleans in August of 2005. He was an embryo contained in a canister of liquid nitrogen, frozen with fourteen-hundred embryos, which police officers rescued from a hospital. He was later implanted into his mother, Rebekah, and born on January 16, 2007 in Covington, Louisiana, some seventeen months later. When Noah becomes an adult and looks back over his life, he can say with all certainty that he was rescued from the flood in 2005. If he had not been rescued, he would not be with us today.
As Robert P. George and Christopher Tollefsen point out, there could even be circumstances in which people agree that it would be reasonable for a particular person to save the embryos, even if other people, including people with no personal attachment to either the embryos or the girl, might be drawn to rescue the girl. For example, say a doctor in the clinic is a father or grandfather to the embryos. Most people would not consider it immoral for that doctor to rescue the embryos over the little girl. And by contrast, it would be seen as immoral for a parent or grandparent to kill someone else’s child to harvest organs to save their own child. 
The authors further suggest that if someone, connected to the embryos or not, were rescued from that facility and grew up to be adults, if they got together on their 21st birthday to honor and thank the person who had rescued them while they were embryos, could the rescuer in good faith accept their praise and gratitude for rescuing them? Of course, as surely as it was Noah who was rescued from the flood following Hurricane Katrina. Finally, what if the choice were three comatose patients or a five-year-old girl? Many people would agree that the comatose patients are humans deserving of full moral respect. Yet no doubt many of these same people would opt to save the girl over the comatose patients. Does this mean, in a different situation, these same people would consider it justifiable to kill comatose patients to harvest organs for a five-year-old girl in need? 
The very fact that pro-life advocates recognize this as a moral dilemma shows that we do, in fact, consider these embryos to be valuable human beings. However, even if we were inconsistent by rescuing the adults over the embryos, this would do nothing to negate our arguments against abortion. So as we see, allowing these embryos to die in the fire to rescue another human does nothing to show that we don’t believe embryos are full human persons, and it certainly doesn’t justify us taking their lives through abortion.
 Stretton, Dean, Critical Notice–Defending Life: A Moral and Legal Case Against Abortion Choice by Francis J. Beckwith. [review article]. Journal of Medical Ethics, 34(11), p. 795, as cited in The Ethics of Abortion by Christopher Kaczor, (Routledge: New York), 2011, p. 139.
 ibid., p. 139.
 Klusendorf, Scott, The Case for Life, (Crossway: Wheaton, Illinois, 2009), p. 42
 Robert P. George and Christopher Tollefsen, Embryo: A Defense of Human Life, Doubleday, 2008, p. 140.
 ibid., pp.140-142.