women are actually stronger than men when it comes to taking pain. if someone is attacking you no matter the gender you have the right to defend yourself. yeah you should go easy on the lady like just block her attacks or get her into a hold where she cant move till she settles down.
but you shouldnt just stand there and let her beat the F out of you. now if its your ex wife and she punches you in the face then go for it all the way. just dont do it infront of the kids.
It's usually not acceptable. I'd say self defense is okay, but even then, exercise caution. They aren't fragile...but there is generally a large strength gap making it a tad unfair.
The worst I've done is tackled a girl for trying to kick me in the nutz.
I used to spare with this lady who was a capoeira user. I blacked her eyes several times, but I tried to avoid hitting her nose. It was sparring and for practice/learning. So I don't consider that the same as what the thread was about. She actually got pissed if I held back..she didn't like being treated weak/fragile.