Mater semper certa est


Mater semper certa est is a Roman-law principle which has the power of conclusive presumption, meaning that no counter-evidence can be made against this principle. It provides that the mother of the child is conclusively established, from the moment of birth, by the mother's role in the birth.
Since 1978, when the first child was conceived by the technique of in-vitro fertilization, the principle of Mater semper certa est no longer applies, since a child may have a genetic and a natural mother who are different individuals. Since then some countries have converted the old natural law to an equivalent codified law - in 1997 Germany introduced paragraph 1571 Mutterschaft of the BGB reading Mutter eines Kindes ist die Frau, die es geboren hat.
The Roman law principle however does not stop at the mother, in fact it continues with pater semper incertus est. This was regulated by the law of pater est, quem nuptiae demonstrant. Essentially paternity fraud had originally been a marriage fraud in the civil code due to this principle. Today some married fathers use the modern tools of DNA testing to ensure a certainty on their fatherhood.