Quite a few Charge Nurses run wards (the male version of a sister, although I believe some female nurses use the title charge nurse too), much like how at one point the title matron had been pretty much scrapped and replaced with ward manager and assistant ward manager, until some numpty thought it would look good on their political CV to "bring bag modern matrons!". Historically however, you would have seen wards full of brothers, as nurses were monks, but that's just history for you. Female nurses came much later. I should imagine it was quite a shock to everybody when women started wanting to be nurses too! I mean, it was a man's job en all, will all that lifting patients around, and having to deal with wounds etc....
Some of you need to stop feeling so threatened, nobody is going to chop off your manhood, don't worry.... :p