It's indeed a title that tried to transition differently than what we're used to read from him. Instead of being darker and more realistic, this one does the opposite by having a style close to newspaper strips and the slapstick comedy cranked up to 11. It was heavily criticized for looking very simple and rugged though, and Tezuka would give it up pretty quickly, only replicating this artstyle in 2 of his other stories: "Ue wo Shita e no Diletta" and "Fuusuke". Like it or not, I think it really suits him and shows how versatile he can be, and whereas most of his adult manga had trouble meshing the comedy bits with the serious story without killing the narrative flow, it works to the perfection here because it really looks like it was made to be absurd and it doesn't take itself seriously despite tackling themes of gender and identity that I don't think were really common at the times.
Inspired by the novel "War with the Newts" by Karel Čapek, Ningen-domo Atsumare also delves into the genre of satire but replaces the idea of a new intelligent species (already explored in Kitarubeki Sekai, one of his earlier manga) with the concept of Eugenism.
Everything starts when Tenka Taihei decides to desert from the war occurring in the fictional country of Paipania (which is really Vietnam). However, it will only take a day before he is catched up by the army and sent to a special laboratory where instead of being executed, he gets some of his sperm collected thanks to a giant milking machine with the goal of making kids born from artificial insemination into special soldiers by brain washing them from their birth. When it is discovered that the sperm from Taihei can give birth to humans that are neither male nor female, a doctor in charge of this project will see in it an occasion to make big profits and will pursue these experiments even after the War in the open as there are no ethical rules applying to this new race.
I think it's really interesting to see asexuals trying to blend into society at different ages, you get to see parents worried about their kids becoming degenerates if they let them play with asexuals and a decade later, you'll be able to witness their sexual liberation and see them hanging out in gay clubs and bars because that's the only place where they can be accepted and where the notion of sex and gender doesn't matter or all and where they can dress or act as they want.
There are also some clever exploitations of this idea of a third race, especially with the creation of an independent state where Tenka Tenhai rules over his sons like Hitler (as you can see if you look at the cover of volume 2) but the whole thing is so burlesque that it seems like a giant nod to Charlie Chaplin and his movie "The Great Dictator". You can also see asexuals being created just to make them kill each other in a big entertainment program retransmitted on radio and television to calm the tensions between countries all around the world and avoid starting a war between real humans, it even explores what would happen if some of Taihei's semen was sold in the black market and used for personal gain.
While I'm not the biggest fan of Tezuka and of his writing that has aged pretty badly, this one is very complete and coherent narratively and it's perhaps one of the only case where his resort to comedy isn't made to sugarcoat the topics he covers but reinforces them by pushing the extremes. I wished more of his manga were like this one but I'll comfort myself in saying that its uniqueness allows it to shine even brighter in his overcrowded bibliography.
