I've done some more thinking on how pregnancy could work, and came to the conclusion that it should be a fetish exp with traits. Yes it would mean that you build 3 fetish up when you are trying to be a dad, but read me out.
The only way to get the fetish exp will be with visiting the girl you knocked up, bang her again, and for her to give birth off screen/how ever Finchy wants to handle that. That would give 1 exp to represent 1 baby, and give the first trait of "unplanned father."
What the trait/title gives I'm thinking is more inital arousal when dealing with a pregnant woman (I've maxed out all traits, so when I start a fight it is 36~47 arousal, what I'm asking is 49~62 starting arousal with a maxed father trait,) more enthralling, and maybe lowered "Pent-up" and "Backed-up" threshold for more mother making loads. As it develops, I'm thinking the flags should be at 1 (Unplanned father), 5 (A dad),10 (Farmer mentality) , 20 (baby daddy) , 100 (Repopulater of towns.)
Obviously, I am not the dev, so it is up to Finchy to thumbs up and do their own thing, thumbs up and copy what he likes, or thumbs down and toss a brick at me.