I think the mom is a regular woman. There is mention of a dad in this game, so the mom has a womb lol. Since Hermas aren't actual hermaphrodites, but futas, the mom must be a regular.
U know, I was kind of wondering, what if somehow the sister was really the dad???
Because if u really stop to think about it, that would explain a little bit (or most) of her tough love dad like behavior towards the mc, in my opinion, not to mention that also could explain the main stories plot with the MC's link to hermas..
& let us not forget that the MC's older sister (the one im low-key thinking can really be his dad, & who might just only appear to look a little younger than the mom because of her haven used that hyperbolic time chamber that the thingamajig, (whatever u want to call it) that the MC threatening to use on himself if his mom & sister(s) were to not to start treating him differently & start giving him some real answers about some things,-) is really, mostly, attracted to girls. Since that's one of the things that we know about her, or at least can assume of about her so far. Which, to remind, isn't like the mass majority of almost all the other Hermas in this story, who which are mainly, really, only attracted to just men instead of women.
& what it is that I have to go & base this off of, just to back that specific part up about the older sister, is from (back tracking just a bit now, just to) the part of the story of where the older sister was trying to sneak around with that female receptionist lady of their family's business. When she was supposed to secretly meet with her in the storage room, with storage room lights turned off, but instead of the receptionist, it was the MC who was the one that went in there instead (can't remember the reasoning right now tho, as to why tho it was him who went in there & not the receptionist but), that which in the end, only ended up causing the older sister to accidentally mistake the MC to be the receptionist lady from the lights being turned off & resulted in the MC basically almost having had been raped because she snuk up behind him in the dark room & covered his mouth.
But to another main point of reasoning as to why I brought that part of the story up, is because if this theory of mine does actually turn out to be true, then that would also explain the reason to why the "older sister" was/is to creeping around so secretly behind closed doors with that receptionist lady in the main lobby of their family's business....
(So that clearly the mom doesn't hopefully find out about the "affair," & ends up chewing off the "older sister's" (or in this case "dad's"

) head off....
& plus, this could also explain maybe why the incest tag is there already having something to do with this whole mystery as well....
My problem (along with a few other others) that kind of don't add up to this possible theory being true, is that I'm a little unsure still as to why they would be necessarily choosing to hide this from the MC.. But then again, that could be do to the reasoning of us not having had came around to unraveling it yet in the story...
But I'm obviously still not fully sure about this yet.,
So, yeah..!
Other thoughts/insights about this possible theory to some of the answers to this whole story's mystery case are more than welcome.....