This happened to me just Monday night...
We have different senseis on different nights - a lot depends on who shows up. Sometimes more senseis than students. All the senseis are expected to assist with training newbies like me.
I happened to be lined up to practice squat kicks (otoshi geri) in a line with one sensei - female. She is in her late 20's, dimunutive, and in very good physical condition. She is an EMT, as I recall.
She was standing behind me when I was kicking. She yelled for me to 'get your hands up' because I was not keeping my guard up while I kicked. I complied - or I thought I did.
A few seconds later, she yelled at me again to 'get your hands up'. At this time, I thought my hands were up - I could not see the bag, because my hands were in front of my face. I said over my shoulder 'they are up'! She said 'no, they're not, get them up'! So, I said, 'what do you want me to do, hold them over my head'? She said 'I want you to do what I tell you to do'.
Now, I am a newbie, and I do not have good form kicking, but I have very strong legs and I kick hard, so I was walloping the bag. She weighs, I am guessing, less than half what I weigh. When it came my turn to hold the bag and she kicked it, she was drilling holes in my head and hammering the bag with kicks that probably would have floored me - flat out. I mean, they were as strong as some of the kicks I've seen our biggest, fastest, meanest, sensei use. WHAM! Lightning fast, very controlled, and strong enough to rattle my cage holding the bag from a safe distance.
Somehow, I guessed that I had screwed up...
After class, I went over to her and apologized sincerely. I told her that I had been rude and disrespectful and said I was sorry. She was still mad, but she said "I appreciate that." I left it at that and went home.
Now, I realized that I made a mistake. She is a woman, but she is a high-dan black belt, dedicated to her art, does not get paid to teach, and she is deserving of the same respect I show the male senseis. In fact, it should not even be a question - what I did should never have happened. She is also, as she demonstrated, more than capable of kicking the crud out of me.
I also realized, upon reflection, that I've cracked wise with the male senseis on occasion in the same manner - and they didn't get mad at me. But it was still disrespectful of me - just because they didn't get mad, they certainly would have been right to do so.
And I also know that in her job, my sensei has to use her karate all the time. She is constantly being attacked or (worse) hit on by drunks and druggies, some of them strong, some of them out of control. She is good - she has to be. And I suspect that she gets disgusted with men in general - they see her as 'defenseless' or 'less than capable' of defending herself, and she has to prove that she can, over and over. So I suspect she might be a tad more sensitive to being insulted or disrepected than some guys. But that's as may be - it doesn't change what I did and make it right.
So I will try very hard not to be rude or disrespectful to her again, and I certainly respect her skills. I have no problems learning karate from a woman half my age and half my size. She has what it takes, and she is worthy of my respect. That is all that matters.