Stephanus,
Do you just want to yank their chains, so to speak? or do you really want to effect some good?
If you want to effect some good, go review the "Opening the Closed Mind" article by Randy Watters at freeminds.org and see if there's something you can use there if these are 'friends' of yours who might actually converse with you. OR, if not, you might want to ask how certain Jehovah's Witnesses can justify [as a conscience matter]accepting all those allowed blood fractions which require HUGE amounts of stored blood to enable the extraction, while they NEVER, ANYWHERE, IN THE ENTIRE WORLD, actually DONATE blood of their own?
If you want to yank their chains, any of hip's suggestions will work.
(There'll likely be plenty of publicity on the pedaeophila issue shortly, so you needn't bring that to their attention.)
Let us know how it turns out.
outnfree