Semi-quick guide for to unlock the pregnancy :
*Note that it will take a few chapters.
1. Fail all failable mission starting from the beginning. Certain key missions that advance the chapter are not failable. Instead the MC will just get teleported to the infirmary.
2. The MC will be then kicked out of the Special Forces, and start the resistance route.
3. When MC gets the chance to murder human NPC's, do so. Kill until Corruption level 3 (this is important I think). Kill whenever possible, even the choices after the boss fights. *You can spam the murder count by exiting an area with human enemy's and then enter it again. They will respawn.
4. Also fail all failable mission in the resistance route (*Not sure if this is required).
5. I'm also not sure if lewdness parameter levels needs to be a high. There is a "cap" and requirements for lewdness level based on chapter. So you can't just max out your lewd level by spamming sex scenes. There are conditions. You can check the conditions in "Elements" which is under the Sex status.
6. After failing missions and advancing the chapters in the resistance route, you will one day get the option to stay in the resistance or go out on your own. Choose to go solo.
7. As you advance, eventually you'll get a cut scene where the hooded emo looking albino guy knocks the MC out and takes her to a lab. The MC will be put in a glass tank where the researcher will modify her womb. Then you'll get to see the first birth scene. *Not sure if you also need to fail missions to trigger the knocked out and kidnap scene.
8. After the first birth scene, the MC will be back in Zilla and you'll get a message that the girl can now get pregnant. Take note that it takes some time for the impregnation cut scene to appear. I once got her impregnated from a human thief customer from the "Escort service" but the scene where the sperms penetrate the egg didn't show until much later.
9. HAVE FUN TRYING OUT ALL THE HYBRID BIRTHS, YOU FUCK PERVERTS!!!! HA HA!!!