Stem Cells: Contrasting Positive & Negative Claims

Today I received and email from a fellow atheist and veteran. He had been having a debate with his conservative father on the social and scientific merits of abortion and stem cell research. He asked me to read the debate, mainly the last dozen posts, and get back to him. His father had him questioning his position on stem cell research.
There was far too much to read, but I read the main points. My friend made a mistake that I see many atheists and skeptics making, I've even made it. The difference between a positive claim and a negative claim is hard to see at times. Not only that, but there are times when a skeptic must make a positive claim that negates the theistic claims. This is the transcript of our conversation...

Jon:
take a look at the conversation between my Dad and I towards the end, the last 10 posts. he actually has me rethinking some of my stem cell stances, let me know what you think. [Link intentionally omitted]

My Response:
In my opinion, you both make mistakes. That's a good reason to change your stance, but I wouldn't adopt his stance. Your father makes good points against your position. He called your position "illogical"... I would refer to it as "unreasonable" since you are definitely making an attempt to be as logical as possible, I just think you're going about it the wrong way. Percentages, time tables, heart beats... who cares!

Where life begins is irrelevant. To the Christians, it's the only thing that is relevant. So that's the argument they grip to. The problem is a moral one. Moral problems are about minimizing suffering. To the Christian, the suffering of babies take priority. To the secularists, the suffering of sick individuals takes priority. The question is not "Where does life begin?"... the question is "Which variable should receive priority?"...

We are faced with two variables, the babies (as Christians define them) and the sick and dying. How do we distinguish between the two? What are their similarities and differences? How do we determine priority?

Here's the argument I make...

The reverence some people have for stem cells is that they believe they are babies, human beings deserving of equal rights and protection under the law. They effectively use the same exact argument for stem cells that they do for abortion. Some people try to spend their time defining what is and is not a baby, where life begins, and when the embryo has rights. That's a bad way to go about it. Instead, just point out the obvious... The sick and dying people the secularists want to help are most certainly people, humans with equal rights, deserving protection under the law, etc... Whether or not you believe the stem cells are people, or have the potential to become people, is still up for debate. Leave that debate to the scientists and doctors, the ones more suited for the argument. As long as the debate is still on going between the "It's a baby" and the "It's not a baby" sides, then the priority lands directly on the shoulders of the sick and dying patients. Perhaps, one day the baby debate will end and the theists will win. If that occurs then we can have the priority debate again and judge the sick and dying against the embryos accordingly. But the fact remains that the secularists have a variable on their side that is without question undeniably human. The theists have a variable on their side that is in question. It's like having a hearing in court and the prosecution came without their notes. They're entirely unprepared and have no case. That doesn't mean there's not a case to have, but if there is, they don't have it. Simple mistrial, the defense is allowed to return to business as usual. Which in this case is using stem cells of all sorts to treat patients.

Your dad is a smart dude. He knows how to twist your words just right to make you doubt your own position. In this case, I think it worked in your favor. Your position was a bit uneven. But remember, the claim here is from the theist/conservative perspective. They claim stem cells have the right not to be used in treatment and research. If you doubt their claim, then you have the negative position. It's not your responsibility to state a case for your position so long as your position remains one of negative skepticism. When you begin making claims about when and where life begins, you're making a positive claim and you must argue it. Stay away from that argument, you're not a neuroscientist. Simply hold the negative position.

There are times when the skeptic must argue a positive position. For instance, when a theist tries to refute evolution. They argue in favor of Creationism/ID and the atheist/biologist argues in favor of Evolution and Abiogenesis. Sometimes it is necessary to make evolutionary claims to refute their nonsense creationism claims. And when we do that we make a positive claim, one that must be supported. Luckily, there have been a million biologists before us that have done all the hard work, and continue to do it. We have the information to support the claim, we need only understand it. However, in the "Where Does Life Begin" debate, we do not. Luckily, we don't make claims without evidence. Therefore, we must maintain the negative position. Let the scientists and doctors debate where life begins, if at all. We will stand our ground and hold the line.
Jon:
He also asserts that adult stem cell research is more promising than embryonic stem cell research, thoughts? 

My Response:
That's a debate for the doctors. The REAL doctors. However, the argument about which is more promising is a funny one. It turns out that adult stem cells might have more potential than those from embryos. However, the embryonic stem cells are easier to obtain, easier to manipulate, cheaper to harvest, and currently more useful. There was once a time when metal products rivaled wooden products. Back when we were changing up our weapons from wooden clubs to metal spears. However, the metal products weren't promising until we could properly manipulate metal and create a sufficient supply of products with sufficient durability. Even when we learned that metal was more promising, it wasn't more practical till later. Same might go for adult stem cells. Till adult stem cells are more practical, embryonic stem cells are the industry standard.