Does Vocab Malone understand the implications of his own position?

Vocab Malone, with whom I had a blog debate about abortion and personhood last year, recently came across this comment of mine on the Point of Inquiry podcast with Jen Roth, an atheist who argues for the immorality of abortion:

Was Jen Roth ultimately arguing that personhood is something that a human organism has for its entire lifecycle? At what starting point? Conception, implantation, or something else?

I find it completely implausible that an organism at a life stage with no capacity for perception, let alone reason, counts as a person. Nor that a particular genetic code is either necessary or sufficient for personhood.

I think every point that she made was brought up in a debate I had with a Christian blogger on the topic of abortion, who similarly argued for an equation between personhood and human organism. I wonder if she has any better rejoinders. Does she think that IVF and therapeutic cloning are immoral? IUDs?

Vocab claimed that my argument was a "Chewbacca argument," a smoke screen, or a slippery slope argument, but in fact it is none of these.  I posted the following comment in response to him:

Vocab:

The argument I made is not a slippery slope argument, it's a reductio ad absurdum.  Your position is that the human organism is a person and has a right to life from fertilization to death (and presumably beyond), so you've already gone down the "slippery slope" and must of necessity say that IVF, therapeutic cloning, and IUDs are immoral because they result in the destruction and death of fertilized ova.  My position is that it is absurd to think that these things are immoral, and if you were to avoid the slippery slope by agreeing with me, you would have contradicted a logical consequence of your own position--thus, a reductio ad absurdum by being committed to a proposition and its negation.

A slippery slope argument is an argument that says your position is committed to some consequence because there is no criterion that you can use to draw a line to avoid.  For example, if I argued that your position committed you to giving a right to life to all animals, and required you to be a vegetarian, or that it required you to give a right to life to every organism with DNA, and required you to hold a position like the Jain religion that all killing is wrong.

As it happens, you never did supply an account of just what it is about the human organism that gives it a right to life or personhood--you offered no constitutive account of what properties entail a right to life or personhood, other than a genetic one.  I made the case near the end of our debate that you are probably implicitly assuming that personhood comes from a soul, and that souls are connected to human organisms at the point of fertilization, but there's clearly no evidence for that position, scientific, philosophical, or theological.

BTW, my argument is also clearly not a Chewbacca argument or smoke screen, which is a simple non sequitur.  To think that, you would have to fail to understand that the items I identified all result in the destruction of fertilized human ova.

It's important to note that not all slippery slope arguments are fallacious--if there really is no criterion to stop the fall down the slope, the argument is valid.  As Vocab never did explain what it is about human organisms that make them rights-bearers, I think he does face the slippery slope argument I presented unless he can offer some criterion for distinguishing human organisms from other organisms with respect to having a right to life.