When I started training Aikido, there was a woman in the Dojo. From my point of view, she was excellent, brave, valiant, quite attractive, and seemed to love Aikido. Since the compasion and special treatments disapeared to her (increased the intensity of training), she became sad all the time, trying to impose her point of view all the time and giving no chance to anyone to disclaim her thougths. There were moments, when she had the menstruation, that the techniques hurted her more than the usual and instead of explaining that, she changed her expression and in a very loud voice used to say, heyˇˇˇˇˇˇˇ, don't do it that rough, don't you see I'm a ladyˇˇˇˇ, and when it was her turn, she did it the rougher she could. I think this must be an special case, so the point is that women have the same oportunities to make the goals, but they need to be understood because their different nature and physical characteistics. I`ve seen very good women doing very good Aikido, and plus the armony it represents, the beauty they add is nice to the eyes. Don't expect a woman be like a man, that's a mistake, but as aikidoka they can be as good as any man.
P.D: I don't think Aikido is a "just for men martial art". If you can feel love you can practice Aikido.