Bear with me on this one, but I think the day a man could call himself a feminist without it raising an eyebrow, discussion nor query is the day feminism is no longer needed.
I do not believe today is that day. Something always makes me cringe when I see men wearing "this is what a feminist looks like" t shirts, although that might have something to do with the most recent examples being politicians, I'll need to go away and pick apart my thoughts and feelings on the matter.
What I will say is that the suffering of women can have an affect on men. If you cast your emotional net wide enough that which causes distress, pain and frustration to those that you care for will have an effect on you. This is what it means to be fully human not just male or female so I suspect you will understand my meaning. It will not be the same as direct experience but nevertheless it is there.
Also there is a crucial element at least for me in that feminism does not resonate with me in quite the same way I believe it does for women. It acts as a portal to a place where conditioned attitudes and beliefs can be challenged, deconstructed and (hopefully!) overcome, and in short find the space to ask the question everyone should ask of themselves which is "who am I?" And the freedom to define your own response.
I can intellectualise how I might "do" feminism were I a woman, and even have thoughts on how to do it differently, but I think without having walked through that portal it's only ever going to be so much hot air. I don't say that meekly, I quite like myself and I value my own thought processes and ideas, but I would like to think I respect the right of other people do do the same.
To put it bluntly I don't think I entirely understand feminism, and as such hesitate to apply the label to anyone, but firstly I'm not in fear of it, and secondly I am aware of a great deal of good that it does. Maybe that's all I need to know...