DURING his lifetime, Sergio Osmeña’s father was unknown or “padre no conocido” in Spanish.

Osmeña, a lawyer and politician, served as the fourth president of the Philippines from 1944 to 1946, and he was the first Visayan to hold the presidency.

Historical documents and archives have pointed to two possible individuals as Osmeña Sr.’s father: Pedro Lee Gotiaoco, a Chinese immigrant tycoon, and Don Antonio Sanson, a merchant and businessman.

But on Friday, June 2, 2023 or nearly 145 years after Osmeña’s birth, a paternity project revealed that his biological father was really Sanson.

This was made possible through a Y-DNA test, a genetic test that analyzes the Y chromosome, which is passed down from father to son. This test can be used to trace a man’s paternal ancestry, or the line of his male ancestors.

The paternity project was initiated by Osmeña’s descendants Maria Lourdes Bernardo and Annabelle Osmeña Aboitiz.

The Y-DNA test was conducted this year with the help of forensic genealogist Todd Lucero Sales. It used DNA samples from male donors representing male lines of Osmeña, Gotiaoco and Sanson clans.

“We began discussing the project in February and started collecting the samples within a week in March. The results were provided to us by the middle of April. So, the whole process took less than a month,” Sales said.

Out of the 23 markers involved in the test, a 100 percent match was found between the Osmeña and Sanson lines, indicating a close relationship and a more recent common ancestor within three to five generations.

Former Cebu City mayor Tomas Osmeña was the donor for the Osmeña line.

“I’m grateful that so many people are interested in this level of detail, but that doesn’t diminish what Don Sergio did for his country,” he said.

Tomas’ grandfather was born on Sept. 9, 1878, when the Philippines was under Spanish rule. According to a Wikipedia entry on the elder Osmeña’s life, he was born out of wedlock. His mother, Juana Suico Osmeña, belonged to a prominent Chinese Filipino family in Cebu. She gave birth to him at the age of 14, and she did not marry his father.

Despite the stigma of being an illegitimate child, Don Sergio Osmeña became a lawyer and politician. He served as Cebu’s third governor before becoming the first House Speaker and eventually the President of the Philippine Commonwealth.