This is probably considered unusual, but I really don't know why.
I'm a man. And I want to be able to lactate.
Not become a femboy. Not being gender changed. None of that.
From what I understand, roughly 1% of men naturally produce enough of the hormone that generates milk, and another 1-2% can be stimulated into that. And, this last number can be increased with hypnosis.
Additionally, if I've understood the research correctly, there are health benefit _correlations_ to being one of these lactators -- I don't know if it's a causal relationship, or if it even applies when the hormone levels are manipulated in this way or not.
So just lactation for men without any of the "become a girl" factors.