I found a bug that occurs when your daughters come of age. I'd been curious as to why your daughters seem to get flagged as slaves as that would not be my personal preference. I assumed that it was just a play style choice so I started digging around to change it and discovered that it's not actually supposed to be that way.
cGirls.cpp:
child_is_grown function
The call to CreateRandomGirl is incorrect.
sGirl* sprog = g_Girls.CreateRandomGirl(12, false, "", slave, AllowNonHuman);
It should be:
sGirl* sprog = g_Girls.CreateRandomGirl(12, false, slave, false, AllowNonHuman);
The 3rd parameter is whether or not a girl should be flagged as a slave, the 4th is an unused parameter for creating an undead girl. The value of "" is evaluated as true, making all of your daughters get marked as slaves rather than just daughters who's mothers are slaves.