Hope you don't mind a view from the other side. I wouldn't have a problem with a male mid-wife but then it would never be my decision anyway. But I do wonder if fathers would be more opposed to a male mid-wife being on the scene than the mothers.
I view this situation similar to if I had see my GP for man problems. I could end up with a female GP. They are a medical professional but they are people too so if I felt uncomfortable, didn't click, whatever, then I may consider another doctor, male or female.
I have 3 kids (ok fathered) and one of the mid-wifes (mid-wives?) at 2 of the births, was old, frumpy, single and had no children. My wife and a few others didn't particular like her. Always matter-of-fact, overbearing bossy type. But she had loads of experience but then I thought she was ok.
But at the end of the day if the mother is not comfortable with a male mid-wife then so be it. I would say for any other medical procedure, it would be silly to consider the gender of the medical staff. But as pregnancy is not a normal medical procedure, ie it's not for attaining healment of an illness/aliment, it is a very personal phenomenon complete with a gamut of emotions, then I would say it would seem quite 'rational' for her to prefer a female mid-wife.