Personally, I'd prefer to have a woman instruct me on techniques. I think it's important to have someone teach you from experience. I personally don't think a man would be able to tell me what would feel good on me, as a woman So, yes, I'd prefer a same-sex instructor.
BUT, by the same token, I wouldn't like having my same-sex instructor perform the techniques on me. I'd be more okay with her showing me/my partner the ropes