It looks like it, yes. (Sorry I'm not intimately familiar with the situation- I'm reporting on what one of our users is saying so I'm having to go and check =).
At any rate, if I change one of the adult children to "child", they do disappear off of the "parents" transformed filter. I will try to find out if there's a reason they must be listed as an adult.

On a related note however, it doesn't look like the "Known Relationship" of "Parent" will cause non-family members to appear in the transformed list. Offhand I can only imagine that being useful for returning the parents of adults (for some reason), but it does seem like that transformation should check those relationships. Maybe this is an option I could turn on, do you know?

Looking at this this seems like good behaviour to me. A second filter that finds those who have parental relationships could be useful. I think the only way you could improve the existing transformation is if you restricted it to returning two adults (those with the greatest ages). There might be some edge case families that you end up returning the incorrect results for though.

After looking at our own example, I agree that it makes the most sense to return all "adult" members of the same family (or families), since theoretically dependents who are nevertheless "of age" who have reason to still be listed in the same family instead of their own, will probably appropriately be categorized as a "child" instead of an adult. Likewise grandparents, aunt/uncles, etc living in the same house should be their own "family" but with the same address. I do think that it should consider and include anyone with a "parent" relationship in the "parent" transformation, but maybe there's a reason to make it a second transformation as you suggest that I'm just not thinking of. Thanks =)

Should I add a suggestion to the black book regarding transformation and the "parent" known relationship?