The instructions with form I-130 indicate that the G-325A is only needed for Husband/Wife petitions, others like son/daughter require a copy of birth certificate.
QUOTE
B. A child and you are the mother: Submit a copy of the child's birth certificate showing your name and the name of your child
C. A child and you are the father: Submit a copy of the child's birth certificate showing both parents' names and your marriage certificate.
D. A child born out of wedlock and you are the father: If the child was not legitimated before reaching 18 years old,you must file your petition with copies of evidence that a bona fide parent-child relationship existed between the father and the child before the child reached 21 years.This may include evidence that the father lived with the child, supported him or her, or otherwise showed continuing parental interest in the child's welfare.
http://www.uscis.gov/portal/site/uscis/men...00045f3d6a1RCRDSo neither G-325A or G-325 are required.