The extended family tree of singer-songwriter Loudon Wainwright III, playing solo at Seattle's Triple Door Sunday, is beginning to look like one of those intermarrying European royal families.

Wainwright sits at the hub of a musical dynasty that includes his first wife, Kate McGarrigle; his second, Suzzy Roche (of the Roches); and his son, Rufus Wainwright. But when Rufus had a child with Leonard Cohen's daughter, Lorca — hey, that was like Henry VIII marrying Catherine of Aragon. (The child lives with Lorca Cohen.)

"We're just acquaintances," said Wainwright of Leonard Cohen, in a phone interview last week from his Long Island home. "Now we're co-grandparents, or co-grandfathers, or whatever the term would be. I suspect we'll be seeing a bit more of each other."

That's a typically dry response.

On his most recent album, "Older Than My Old Man Now," an eloquent meditation on mortality, there is a song called "I Remember Sex." Tongue-in-cheek, surely, right? (Wainwright is only 65.)

"Well, I had to put my tongue somewhere," Wainwright commented.

Humor is one of Wainwright's staples, starting with the 1972 novelty song, "Dead Skunk (in the Middle of the Road)," his first (and only) real hit. He grew up on comic singers such as Tom Lehrer and Allan Sherman.

"The novelty songwriter had a bit of a cachet," he said. "And if you go back and listen to 'Poisoning Pigeons in the Park' [Lehrer], it holds up. 'Hello Muddah, Hello Faddah' [Sherman] holds up. It has a tensile strength to it."

One of the best new songs is a duet with the great "cowboy" folk singer "Ramblin' " Jack Elliot, "Double Lifetimes" ("I want a double lifetime, I wasted my first one"). But Wainwright plucks more serious strings on "All in a Family," when he sings "Forgive and forget, and finally see/the forest from the family tree."

"People in your family and people you are close to have the ability to hurt you," he reflected. "But forgiveness is an important thing to work on. Because I think you can't forgive yourself unless you forgive these other people."

Paul de Barros: 206-464-3247 or pdebarros@seattletimes.com

Information in this article, originally published May 20, 2012 was corrected May 21, 2012. A previous version of this story stated that Lorca Cohen carried a baby for Rufus Wainwright and his partner. The child lives with Cohen.