I am a man in my 20's. At the moment, I am seeing people casually, because that's the kind of relationships I currently want and have time for.
I have been wanting male birth control for a while now.
As a guy I feel like a lot of what we are told as teenagers by our parents, and so on is that what ever you do, dont get someone pregnant. It will ruin your life, and probably the life of the child.
I know many people who have had pregnancy scares with people who were keen on keeping the child, without discussing whether the male counterpart felt similarly.
If men had the ability to control whether they could get someone pregnant, it allows them to live their lives, enjoy themselves, and explore without fear of negative life changing repercussions.
I'd imagine the arguments for women's birth control back in the 60's (70's?) were similar, with the added issue of carrying the child.
I'm not sure why male birth control is so controversial here on this forum, and in general, it sounds like the arguments for both sexes are similar, and having control of ones own body is never a bad thing.