From the AKA forum (there is DST input as well in the thread)
http://www.greekchat.com/gcforums/showthread.php?t=4019
From the Delta forum (Can Siblings Join Different Sororities):
http://www.greekchat.com/gcforums/sh...ad.php?t=28917
From the Kappa forum (Siblings is the title but there is an off spin for mothers/daughters)
http://www.greekchat.com/gcforums/sh...ad.php?t=74387
There are probably other threads but these are the three that I remember.
Ultimately it depends on that mother and that daughter. If my daughter chose something other than Delta, I would still love her (of course) but it would sting to see this was something that we did not share.