When may illegitimate children use the surname of their father?
xxx it is clear that the general rule is that an illegitimate child shall use the surname of his or her mother. The exception provided by RA 9255 is, in case his or her filiation is expressly recognized by the father through the record of birth appearing in the civil register or when an admission in a public document or private handwritten instrument is made by the father. In such a situation, the illegitimate child may use the surname of the father. (Grace Grande v. Antonio, G.R. No. 206248, February 18, 2014)