I don't know. Not everyone can endure six sex acts in a row, I mean clients
Also I don't see much difference between incresing the number of sex acts per client and increasing the total number of served clients per shift. Except some texts maybe, but outcome more or less the same.
Children and pregnancy... Probably the only way to implement it is to use random girls as daughters, like in WM.
Pregnancy pictures are very rare too. Not to mention that we use days, not weeks like in WM, so pregnancy and adulthood will take a lot of turns. 9 months + 16 years = 6110 turns.
Thus, some kind of trick is required here, but I'm not sure which one.
I didn't think realism was a goal for this game

But you could make it such as the girl is disappointing by the client but she was smart enough to get the money for all the sex acts, although he came in 5 seconds... Besides I was suggesting Intelligence was the stat for this anyways, so it could be logical.
I didn't aim at replacing the number of clients per shift, if by that you mean Action Points per Day, but adding to the complexity, so you would have both, ok maybe endurance should also be some sort of a stat that links to this, if the girl has too low an endurance she could still convince the client to go all out, and if the client actually can, she faints and he leaves dissapointed... maybe the complexity is too high, it is just a suggestion
Regarding the pregnancy, I was aiming at it being more end game material, and it depends on play style, and how fast the game evolves, some like me would take ages, others that don't use auto-save would be there in a few days of play time. Maybe it could be an Easter Egg that only hardcore players can undertake, and girls could have sterile as a trait, if there aren't pictures. I know how long it would take but I would play for it, idk how many other people would but you could have a mystic flask that you can win as a random event, that could add 1 or 10 or more years to a girl, or have the opposite effect.
Also I don't really know what the aim is for game play time for us players, are we expected to quit the game in 1000 turns, or finish it that fast? or maybe restart it? cause if not, 6000 is nothing in the grand scheme of things, but if the play time is reduces to an average of 1000 even 6000 it might be too much. But with all the load / saves I did, I would have passed that a long time ago.