4. Relationship within the prohibited degrees.
Consanguinity and Affinity.—Marriages are prohibited between ascendants and descendants; between brothers and sisters of the whole or half blood; between uncles and nieces; aunts and nephews, and all other persons related by blood or marriage within the third degree.
The laws of Mexico recognize no relationship other than one by consanguinity and affinity.
Each generation constitutes a degree, and the series of degrees constitute the line of relationship.
A. A marriage is prohibited when either of the intending parties has a husband or wife still living.
B. If one of the parties has made an attempt against the life of the husband or wife of the other with the intention of marrying the survivor.
C. If one of the parties has obtained the apparent consent of the other by fear, coercion or duress.
D. If either of the parties is permanently and incurably insane.
Formalities.—Parties intending to conclude marriage must personally appear before the judge of civil status of the domicile of either party, and state their intention. The judge will thereupon make an entry in a register kept for that purpose of the names, occupations and domiciles of both of the contracting parties, the names, occupations and domiciles of their parents, if the same be ascertainable, the names, occupations and domiciles of the witnesses whom the parties present to the judge as knowing the legal capacity of the parties, and proof of the consents of the parents, or of such persons as are lawfully exercising the rights of the parents.