what is offspring base beauty based on? is it the mothers' base beauty? if so, is it the base beauty before any modifications such as the lab improvement / tatoos? example : get a random npc, with base beauty 55, uses lab to incease to 85 and then tatoos to 100. will the offspring base beauty be 55 or 100?

As far as I can see, it's randomly either the mother's beauty or the father's beauty. And by beauty, I mean post surgery and pre kimono/tattoos.

So the answer would be either 85 or the other parent's beauty.