I am pretty sure you need underage content DLC since version here doesnt have underage content. From what i have read pregnancy ends with a baby(IRL experience) and since this version doesnt have babies in game, it just skip motherhood and you will have 18+ fully grown native. I think mothers milk is produced after birth when baby is still a baby.well, i forgot say i have native female/women inside milker, who was pregnant and was giving birth. and near it is npc who is worker for livestock with food+water but still not milk.