Parental discretion is advised.

Yes, we have a real pistol at the Edmonton Folk Music Festival this year - one Martha Wainwright, whose hoped-for performance of her new song Bloody Mother-f--ing A--Hole is as hotly anticipated as joining hands and singing Four Strong Winds at the end of it all on Sunday. She didn't play it recently when she opened for Loretta Lynn, whose fans might not have understood, but she says she'll play it at the folk fest.

The tune is somewhat inspired by her dad - actor, musician and black humour specialist Loudon Wainwright III - and a heck of an introduction to the last member of this amazingly musical family to release a full-length album. The success of brother Rufus is well documented. Both mom and aunt - Kate and Anna McGarrigle, respectively - are Canadian folk stars of the highest order. So Martha's excellent debut album has been greeted with as much enthusiasm as the last marriage in a clan of Hutterites. It is also the first album from this family to sport a "parental advisory" sticker, so it won't be sold at Wal-Mart.

Interesting way to start a career.

Bloody Mother isn't specifically about her dad, she says, though he's written lots of songs about her. One called Father-Daughter Dialogue even stemmed from an argument. Think of this as her side of the story.

From her home in New York City, Wainwright says, "It's not really directed at anybody. It was mildly inspired by a feeling of not being taken seriously. I wrote the song when I was 24, which I think is a pretty normal time to be upset at one's parents."

The four words at the end came in a "moment of inspiration - when that happens you can't deny it."

There is also an element of, if not jealousy, exactly, then at least a desire to follow the family path.

She goes on, "In retrospect, I think the song was almost directed at me, to be able to convince myself that I was good enough or strong enough to do what everybody else around me seemed to be doing, to puff myself up for the battle. Funnily enough, I find people in the press interested in who it's about. But what's amazing to me is that the song has really taken on a life of its own. I don't think people in the audience are particularly interested in who it's about because they would rather think it's about someone that they know. I think that's why people like it."

There's a lot more to like about Martha's album - a masterpiece of melody and wordplay and a special treat for those who love sad songs. Bloody Mother is just one of the sad songs on the entire collection of melancholy fare. Not since the Eels' It's a Motherf---er has there been such a sad song with such language.

"Sad things can inspire me to write. It's very soothing," Wainwright says. "I find that the songs generally start with a loneliness or sadness, but they always end in hopefulness.

"That, I think, is good. I don't want people to think that I'm morbid, but I think the sound of sad is nice. Maybe people need to have deep thoughts."

As for having waited such a long time to release her own album, she says, "I'm glad I waited. I think it happened when it needed to happen."

Wainwright had previously released two EPs of material, was on tour with her brother - who got her a gig as a '40s lounge singer in Martin Scorsese's The Aviator - and was generally enjoying "postponing work until it became really necessary for me to make a record."

It also took some time to find the right guy to produce it, on spec, and the right record label that wouldn't muck with the results. The last thing this artist needed was some marketing genius making helpful suggestions on what she could do to sell it, she says. Rounder Records turned out to be the right label - which happened to be dad's label for a time during the '80s.

Talk naturally turns to this interesting family in which music seems genetically ingrained. Wainwright says it helped a lot that "I didn't live with Loudon," and that Kate concentrated on raising her kids instead of being a touring musician, which made for a "nice upbringing that wasn't too tormented."

So here's an obvious question: do mom and dad like their daughter's new record? Does she care?

Wainwright says, "Yes and no. It's nice to have people like it, and for a long time I think I was intimidated and concerned with what they might think. And that probably created a paralysis for me to a certain extent. I got to a certain point where I was ready to make a record and also to separate myself from their judgment. I think that helped a lot, too. Anyway, they happen to like the album, so I guess I lucked out."

Family reunions must be fun.

Catch Martha Wainwright in sessions Saturday at 11 a.m. on Stage 1 and at 5 p.m. on Stage 3. On Sunday, she takes part in a session at 11 a.m. on Stage 6 and performs a concert at 1 p.m. on Stage 2.