Female Prisoners are essentially female sprites of the male prisoners.
They have slightly different needs and can sometimes have a baby. They will usually only have babies if they are in low-security as in real-life prisons, but they must not be a threat to the baby. Co-ordinating with this fact, the mother is usually in jail for much less than a year.
If they have a baby the AI will change so they service the baby's needs first. A baby will live with its mother in a Family Cell and spend most of their time in the cell or Nursery (essentially a canteen for the mothers).
The female prisoners also come in different shapes and sizes.
Female prisoners were added in Update 2.