It originated in South Korea out of the #metoo movement.
4 B comes from the Korean 'bi' meaning NO, followed by four things; no heterosexual dating, sex or marriage, and no childbirth.
It's intended to highlight and turn away from sex inequality.
It's currently being talked about a lot in the USA...
I wonder what the effect might be if this took off?
More women in female communities, maybe non religious convent type communities?
Probably an increasing rise in incel behaviour and assaults?
Also a knock on effect on dating aps, bars, clubs and their income?
What else?
https://www.independent.co.uk/life-style/4b-movement-trump-election-win-south-korea-b2643558.html