The most widely cited origin of "son of a gun" traces back to the British Royal Navy in the 18th and 19th centuries. On smaller naval vessels, pregnant women accompanying their husbands were sometimes forced to give birth in the cramped spaces between the broadside guns to keep gangways clear. Boys born in these conditions were often referred to with slight contempt as "sons of a gun," particularly when their paternity was uncertain.

Over time, the phrase shifted from a literal maritime descriptor to a mild euphemism for "son of a bitch". Today, it serves dual purposes:

To describe a rogue, scoundrel, or someone who is tiresome .

Son of a Gun | Phrase Definition, Origin & Examples - Ginger Software

The phrase "Son of a Gun" has evolved from a specific maritime origin into a versatile idiom and a common title for works exploring themes of heritage, violence, and survival. Whether used as a mild euphemism, a gritty memoir title, or a cinematic trope, it consistently bridges the gap between rough origins and the identities people build from them. Etymological Origins and Linguistic Evolution

In creative works, the title often symbolizes the inescapable weight of one's background or the violent environments that shape a person.