Actually, I include everything listed to be a sister, daughter, or granddaughter. I should have been clearer, but in my own life, I don't differentiate between blood and legal relations, and I don't think our groups should either.
I am more surprised by nieces, cousins, that sort of thing.
(and good catch, Erin, on the great-granddaughters...there just can't be all that many of those)