Mary said:
The burden of proof is completely on the Hindu fundamentalist to show the cow is sacred, just as it on the pro-lifer to prove the zygote is sacred.

My response:
I’ll give a straightforward answer to this, but we’d probably differ on the burden of proof thing, since pro-lifers aren’t arguing that a separate species is for some reason, sacred. We’re arguing that the species everybody agrees is sacred, (I prefer the term valuable,) doesn’t become more sacred gradually through life. 

I think the species we agree is sacred is equally sacred at ALL stages of life, which erases the confusing philosophical issues that come up with personhood arguments, like why is a newborn suddenly sacred but a fetus in the woman’s body is not, most of those arguments disqualify infants from having the right to life, etc. 

I understand where you’re coming from though, because it probably seems kind of radical to look at a picture of an embryo and inquisitively ask, “that is sacred? Really?” But I haven’t yet heard a persuasive argument for why something slowly becomes more and more valuable, instead of being valuable based on the entity’s own nature.