I Won’t Go Into the Washroom Even If You Beat Me to Death

When Luke had had his suspicions long ago, he got his hands on Phil's DNA and did a test.

He compared the results with his, Catherine, and Drax's DNA.

At the same time, Grandpa Drax, Kevin Coulson – Luke's father – and Phil… all had very high hairlines.

That was also why Luke started to pay more attention to his hairline after suspecting that he and Phil were related.

From his forthright grandfather, he learned that Phil's father was probably his grandfather's younger brother.

In other words, Phil and Luke's father, Kevin, were cousins.

However, Drax never brought up his brother, much less his nephew, Phil.

On public record, Grandpa Drax's brother died fifteen years ago, right after the deaths of Luke's parents.

And according to the information on Luke's granduncle, he didn't have any children.

The implication was clear — Phil had joined SHIELD at that time.

The information had been modified to protect his family.