Partus sequitur ventrem means that a baby's legal status is determined by the status of its mother. This means that when a baby is born, the baby will be seen as having the same legal rights and responsibilities as its mother. So if the mother is a citizen of a country, the baby will also have the same rights as a citizen; if the mother is a slave, the baby will also be a slave. In other words, the baby takes on the rights of its mother.