The adopted girl must have had brown eyes, and her adoptive parents brown.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
that should read: The adopted girl had brown, and the two parents had BLUE. Two blue eyed parent can NOT have a brown eyed daughter.
All this confusion over eye color is enough to Make My Brown Eyes Blue!
Yes, I had them mixed up. See my post #51.
That's the old conventional wisdom. It's turning out that eye color inheritance is much more complicated than the simple dominant brown vs. recessive blue paradigm. In fact, blue-eyed parents CAN produce brown-eyed offspring (even in the absence of adultery), albeit this is fairly rare.