The author at SquareState.net:: Anchor Blastocysts has got a good legal argument that I hadn't heard before regarding the movement to classify a fetus as a legal person from the moment of conception. The purpose of the rule is of course to make abortion legally murder. But there will be unanticipated consequences.
If the “Blastocysts are people too!” ballot measure passes in Colorado, the moment any undocumented worker gets pregnant, not only is that Blastocyst a person—it's also an American Citizen!
Aside from the not-so-small point that citizenship is a federal issue and it is not clear from first principles whether the federal rule should or would follow the state rule, there's obviously something powerful about this logic especially if the Colorado model were ever to be adopted on a national basis.
In that case, if a noncitizen female conceives a child in the US, presumably it would be wrong to deport the blastocyte or fetus. And that means we can't deport the mother either. At least until the kid is born after which we are, as news reports from all over show, perfectly willing to deport mothers of small citizens if the mothers lack proper documentation.
I should add that, while powerful, this logic is not inevitable. Anglo-American law has in the past been able to make various distinctions about the unborn. Although not persons for most purposes, the inheritance laws, for example, extended to children “en ventre sa mère” (the absence of the “de” is not a typo; this is Law French, not the real thing). So it remains possible that the same people who deport nursing parents, leaving the citizens to fend for themselves, would have little trouble finding a theory to deport the unborn citizens as well. Pointing to the problems of proving domestic conception (the mind boggles) is only a first step….