@Cregt,
Bingo! OK, we've got an inference of a hidden agenda in this question. Obviously, you feel these clowns are using this against either you or their daughter, or perhaps both.
The quickest, most effective way to deal with this is just to ask them what the scriptural basis for their claim is. SHOW ME THE MONEY! Ask them for chapter and verse, and have your bobble there ready to hand to look it up, and then dispute the matter with them. They're peddling bullshit--so call 'em on it.