I was curious enough to go to the DAR website to see what they said about adoption and membership, if anything. The membership requirements are pretty clear:
Any woman is eligible for membership who is no less than eighteen years of age and can prove lineal, blood line descent from an ancestor who aided in achieving American independence. She must provide documentation for each statement of birth, marriage, and death.
And then in the FAQs, there's this:
Q. I'm adopted can I still become a member?
A. Yes, but only through your birth parents' lineage, not that of your adopted family. All lineage for DAR membership must be bloodline descent.
The FAQs seem like deliberate cruelty -- prove your lineage through your birth parents in the U.S. where we seal original birth certificates of adoptees. That'll happen, right?! (But on the other hand, I know of a case where a court found "good cause" to unseal an adult adoptee's birth certificate because the adoptee had reason to believe he was of American Indian ancestry and wanted tribal membership. Putting aside the fact that adoptees should be able to access their birth certificates any time they want, for good reason or no reason at all, maybe adoptees can petition to unseal birth records to prove eligibility for DAR?)
This isn't an issue that will affect us. Not only am I not a lineal, blood relative of a Revolutionary hero, I'd be completely uninterested in joining even if I were. But if you know adoptive parents who are members of DAR or organizations like it that disallow membership by adopted descendants, maybe you could pass this information on to them. I'd like to think that any AP would immediately end thier relationship with the DAR on receipt of this information.