Thanks, Brian. That makes sense, even to the non-scientific mind (like mine).
Notice how one of the people they interviewed tried to use the redefinition of "conception" against Dr. Kahlenborn's main point:
Jessica Arons, president and chief executive of the Reproductive Health Technologies Project, said the study authors seemed to be crafting a political statement to push their “radical notion” that Catholic hospitals should not use EC for rape victims.
“However, [the Linacre Quarterly authors’] definition of abortion to include interference with the implantation of a fertilized egg is outside the medical mainstream, said Ms. Arons.
“Whether LNG-EC disrupts ovulation, interferes with fertilization or prevents implantation is irrelevant, since all three function to prevent pregnancy under established medical definitions,” she said, adding: “No matter what patina of science they attempt to use to cloak their ideological intentions, the bottom line is this: LNG-EC works only to prevent, not end, pregnancy.”
Dr. Kahlenborn's position has only been outside the medical mainstream since they deliberately and with malice redefined these words in the recent past. They've been working on this verbal engineering since the late 1960s. Readers can see this 13 year old thread here for more on the subject:
Medical dictionaries redefine "CONCEPTION" to obscure the TRUTH regarding contraceptive technologies