Responses
What was the other manga name with similar premise?
It's not this, it was one of those smutty anthology series from years ago or something. It was the first Omegaverse story I read and the explanation stuck with me.
Well I take that back. It's Omegaverse, but an origin story of how it started.
I didn't think it was. I had a theory going that the male pregnancy thing was caused by the pharmaceutical company and they built a cult around that.
I remember reading another manga's premise for why the ABO spectrum happened and it was pretty much the same; nature responded to low birthrates. However the one I read was more like due to less and less females not being born the ability to sire and conceive was spread out to the opposite sexes as secondary traits.