What are the requirements for my daughter, son or daughter to have the details of both parents?

The requirements for registration in the civil registry of birth of the second maternal or paternal filiation, in the case of same-sex couples, are required: 

1. Yes no has been civil registration has been carried out The child must be presented with: 1. 2. Certificate of live birth or declaration of two witnesses to the birth. 3. Copy of your identity documents, indicating under oath that the child was born into your common-law marriage or marital union. 
2. Yes already has a civil registry If you have a birth certificate in which only one parent is listed, you must: 1. Indicate the civil registry number of the child's birth. 2. Provide a copy of their identity documents, indicating under oath that they were born into a common-law marriage or marital union.