My reasoning is that, in the current immigration fight, Democrats and the MSM (redundant, I know) profess to hate the term "anchor baby" as used to describe a baby birthed by an illegal alien woman for purposes of "anchoring" her family onto US soil (and benefits). And, of course, Democrats when speaking of abortion never use the term baby, preferring to call it a fetus. Thus, the anchor fetus. A way to describe a child born on US soil to the mother of an illegal alien, phrased in a way that a Democrat should approve of.
I used the term several times last night in various Twitter conversations, one of them being in response to radio host Mark Levin, and hey presto!
"MARK LEVIN ON ‘ANCHOR BABIES:’ THE LEFT PREFERS ‘ANCHOR FETUSES’"
(and yes, I did do a Google search to see if the term was in use prior to my Tweets last night: nope).