Maddo_scientisto said:
If his mother was a Quincy, grandfisher would have gotten destroyed, there's no way she would have died by the hand of such low level hollow.
I like to think that Ichigo's mom is just a normal human Isshin falled in love with. Ichigo's birth wasn't a normal one, he probably was the result of experiment and such. Isshin couldn't stand it, took Ichigo and left for the real world where he met Ichigo's 'mom', they fell in love and he had 2 babies with her.
Something like that.
http://www.mangareader.net/94-49233-20/bleach/chapter-397.html
This.Ichigo is an offspring of Shinigami AND - who? (i don't think hollow, it would be too stupid and simple) -.- there is no time for experiments, he was somehow special from the very second of his birth.
There are only 2 choices...or they did experiments on Ichigo's mother (why would they, if she is only a normal human?), and because of that Ichigo is special, or his mother was someone special to begin with, for example Quincy or some relative to Royal people.