Where did you find this? Is this from the raws of another volume or a sequel series?
I saw the link posted in one of the comments but also googled on my own so i read upto vol 3 (which was the 2nd-3rd gen already) plus depending on the translator, the text can be irritatingly polite or more familiarly English with swear words lol. And yes, most of the pedo-grooming-messy interrelationships are 2nd to 3rd volume. Except there are also a lot of "if he wasnt young—"mindset from the bear and lion in vol1 light novel. The manga is just more wholesome compared to the text
I read vol 2 in https://knoxt.space/ai-o-ataeru-kemono-tachi/
Vol 3 in https://blsnacks.wordpress.com/ai-wo-ataeru-kemenotachi/
Like youd think its heartwarming and all that shit with consent and unconditional love. And it WAS most of the time as i did read the first volumes of the story. But it gets so warped when the babies are born. Consent is nothing but an illusion. Chika, a modern man who i think should at least still have the modern intellect of child development, shows hesitance when his nephew shows interest in his newborn human baby. BUT he is only ever so mildly concerned about them being cousins and even nods to "I'll wait for him to grow up". CHIKA, a modern 40 yr old man regardless of his sex slave trauma who even has the tiniest idea of what consent is, proceeds to let an adult groom his kid(S). This world broke our MC so much that even if he has anger towards being forced, his "all's well that ends well" worldview is magnified to the point to the point of simply accepting everything. The author's pedophilia shines more and more in this 2nd generation. Author lets the mc be so naive that it normalizes everything. But of course, the bottomline is violent rape :)