I know others have mentioned Human pregnancy before, but I've got a specific idea about it. First, the father/sire is Evelyn. Second, to unlock it you must have already given birth several times, somewhere between 5-10 times based on writer preference, and sexed her enough that she trusts you enough to talk about her past. Eggnancy's do not count towards this, Butt or otherwise, excepting fertilized Ovilixer. Then, upon visiting Evelyn while not pregnant and not sterile, a scene occurs wherein she expresses jealousy that you're going out there, spreading your legs for anyone and everyone and bearing their children, and that now it's her turn to put a kid in you damn it! She then reveals that she's taken several alchemical mixtures to boost her potency, then spends the next few hours repeatedly taking you until you're pretty much guaranteed to be pregnant.
Also, I'd like to see more acknowledgement of your pregnancy in general beyond certain interactions with the sire, for example if you visit Kiyoko while pregnant, if she's not pregnant then she expresses jealousy, and if she is then she talks about how she likes being able to share being pregnant with you, stuff like that.
Finally, from a lore perspective, I'd really like to see a codex entry for Humans, and I'd definitely love more info on the Godswar, given that we seem to be gearing up for Godswar 2.0.