In 2023, 23,734 or 48.91 percent of the 48,528 registered births in Camarines Sur are illegitimate. This shows about ten percent increase from 2022, where 21,790 or 47.97 percent of the 45,421 registered births are illegitimate.

According to Article 165 of the Family Code of the Philippines, “children conceived and born outside a valid marriage are illegitimate.” Children born of couples who are not legally married, or of common-law marriages, and/or children born of couples below 18, whether they are married (which marriage is void) or not, are considered illegitimate.

From year 2015 to 2021, the number of illegitimate births is continuously increasing, from 46.96 percent in 2015 to 50.49 percent in 2021. Nevertheless, there is a sudden decrease in illegitimate births in 2022 with 47.97 percent. About 212 thousand registered children in Camarines Sur from 2015 to 2023 were born out of wedlock.

The highest proportion of illegitimate births in 2023 was registered in Ocampo with 70.25 percent or 536 out of the 763 registered births, while the least was registered in the municipality of Camaligan with 17.19 percent or 11 ilegitimate births out of 64 registered births.

Other municipalities with highest proportion of illegitimate births are San Fernando with 63.35 percent, and Buhi with 62.11 percent. Meanwhile, the municipality of Milaor recorded the second lowest proportion of illegitimate birth at 18.75 percent, followed by the municipality of Gainza with 22.33 percent. 

In 2015, 76.23 percent of the births recorded in Lupi are illegitimate. This is the highest percentage of proportion of illegitimate births recorded in the province from 2015 to 2023. Gainza, on the other hand, recorded the lowest percentage of proportion of illegitimate births with 6.90 percent in 2021.

Of the 35 municipalities and two cities in Camarines Sur, Naga City recorded the highest number of illegitimate births for 2023 with 7,399 or 31.17 percent of the total illegitimate births in the province, considering the presence of most hospitals in the city. This was followed by Goa with 1,098 illegitimate births or 4.63 percent to the total and Cabusao was third with 1,087 or 4.58 percent share.