Good question... Yes sometimes I do have difficulty deciding what sex I am dealing with. The reason I find is, not because I can't determine what sex they are (as they usually are pretty adept at communicating) but I may be aware of one energy more than another. What I mean by this is; at the beginning of a reading lets say I am aware of three energies. Two are males and one a female, now the problem can arise that they interchange with the messages and I may not pick up the fact that it is coming from someone different.
Sometimes I become aware of the dominant energies (people) at the beginning of the reading. If your father comes through really strong, I might not be aware that Uncle Charlie is now talking as it may still be Dad's energy that I am physically picking up on. Normally those communicating are pretty good at indicating which sex they are as well as their connection to you. I hope I have answered your question.