Present it in a way that is not offensive or accusatory.

There is (at least in my mind and many others) an inconsistency in our position statement. I believe that there is considerable evidence that so-called birth control pills (BCPs) do have a significant post-ovulatory (abortifacient) effect. 

Combination pills contain both estrogen and progestins.

As a prolife physician who shares Randy Alcorn and your concerns about "birth control" pills. Some of my thoughts...

Amidst an ongoing debate among prolife advocates about whether to classify the Pill as an abortifacient or a prophylactic, pro-abortion advocates have published an authoritative statement declaring that the Pill prevents implantation of embryos, thereby causing an abortion. 

Christians are increasingly being exposed to the medical and theological debate concerning the potential abortifacient effect of the birth control pill (the Pill).

This resource is available from the Center for Bioethics and Human Dignity: The Pill: Addressing the Scientific and Ethical Questions of the Abortifacient Issue

...it has become glaringly apparent that now is the time for us, as an organization, to sail into the dangerous and uncharted waters that we have, perhaps intentionally, avoided.  These are the “waters” of prolife principles as they relate to fertility control.