I don't see why this scenario is any different to one where a male is teaching a female. I'm a female and also a black belt in Karate and I regularly teach at my local Karate club and no one has ever treated me different because of my gender.
I prefer to learn from men. Infact looking at it now everything i have learned apart from spanish is from men. I would never learn martial arts from a woman though. lol at that even crossing my mind.
Why should it matter? The fact that they have the black belt shows that they have gone through the system themselves and earned the right to share their expertise. Why should them being a woman mean anything?
It's not really a problem if you practice for sport, but if it's for self defence then it might be; 99.99% of attacks are not going to be from females, so learning moves from someone with those kind of mechanics isn't going to be ideal.
Why should it matter? The fact that they have the black belt shows that they have gone through the system themselves and earned the right to share their expertise. Why should them being a woman mean anything?
I think having a woman as an instructor would be better than a man. In my experience women (who train hard) generally have better technique than guys at a similar level, because they cant rely on strength. If a woman has achieved multiple black belts and made it to an instructor level, she's had to fight and train against guys much bigger than her. She's had to be exceptionally good because otherwise she'd just get thrown around.