“There is no way to assess whether ovulation has taken place or whether an ovum has been fertilized”
Not true. Women’s hormones change based upon their cycle. luteinising hormone (LH)can be used to predict ovulation very accurately. The presence of other hormones can be used to determine at what point the cycle is.
There is some evidence to contradict the evidence presented in this article, and there is some doubt that Plan B prevents implantation. It isn’t 100%, but it is substantial, and possibly these bishops were persuaded by this evidence. I can see having doubt enough to reject the use of PLan B, but to claim there is no way to assess whether ovulation has taken place is 100% untrue.
Anything less than 100% certainty is an unacceptable risk that innocent life will be taken.