Dateline–San Francisco

birthday celebration for a new breed of domestic partners.

The Cat’s Alley Club in San Francisco’s leather-and-platinum SOMA district is closed on a Monday night for a private party. It’s a birthday bash thrown by a local multimedia tycoon for his companion.

Inside, the staff is busy lighting candles and setting out hors d’oeuvres. A bartender wipes down the bar and carefully lines up shot glasses filled with a white liquid. A DJ starts to spin an eclectic mix of classic soul and country-fried rock. Jose Marquez, the party’s host, fidgets in a corner, calming his guest of honor as the two wait for the first invitees to arrive.

At ten minutes past nine o’clock, the door opens and a young woman wearing stylish spectacles and platform shoes breezes through the door. Along with her orange vinyl handbag and a meticulously wrapped present, the guest carries a large plastic box. After setting her present on the gift table, she approaches her host and asks, “Am I just supposed to let him out?”

Márquez suggests that a leash might be in order, at least until “Boo” gets used to his new surroundings. While Boo emerges from his carrier wearing a tether, the host’s own cat, Mus-Mus (pronounced Moose-Moose), is free to roam the vast, darkened club. But then, Mus Mus is the birthday girl.

By ten o’clock, the fashionably late revelers have all arrived with their kitty-cat companions in tow. At least a dozen felines and twice as many “parents” are imbibing the cross-species amenities that Márquez has arranged for the club to provide.

At the open bar, sweetened and salted varieties of milk are served to the cats, who perch in special booster seats while a bourbon-based cocktail dubbed Milk Punch is administered to their humans. Catnip has been liberally sprinkled on the floor in what the club manager describes as the “stoner corner.” Electronic music is now playing at full blast, peppered with audio samples of meows and purrs. Naturally, there’s sashimi and sushi galore for all of the guests.

Even in a city that prides itself on being the “nontraditional relationship” capital of the world, this unusual birthday bash for a 2-year-old named Mus-Mus is a bit over the top. But then again, just a decade ago, the idea of sending a kitten to the therapist or dropping a puppy off at canine day care was similarly unthinkable. As pet owners grow increasingly accustomed to lavishing luxuries upon their animals, full-blown cat and dog parties are on their way from the fringe to the mainstream.

“The pet-related service sector has experienced tremendous growth in the last few years,” reports Dev Chalworth, an analyst with Bain and Company who has interests in the pet-care industry and once named a limited-liability corporation after his cat. “In a strong economy, more and more young workers can afford to live alone. Combine this with greater disposable incomes and a trend toward starting a family later in life, and you find that people are having more pets and are willing to spend big money on them.”

Indeed there’s ample evidence in Márquez’s entourage to support this appraisal of the companion-animal market’s demand for high-end goods and services. From pharmaceuticals to beauty-care products to gourmet cuisine, many of the cats in attendance are as spoiled and fussed over as an only child. Partygoer Anne Etheridge went so far as to sedate her feline friend to preempt any unforeseen social anxieties. “My cat Darlene is a female orange tabby,” the thirty-something ad agency executive says. “They’re one in 10,000. She’s pretty high-strung so I got her some Valium from the vet before bringing her down here tonight.”

The Valium appears to have worked, as Darlene slowly licks the pâté icing off of the tuna fish flavored birthday cake. Six other cats join her in devouring the specialty dessert while the rest of the feline guests help Mus-Mus tear into a giant, mouse-shaped piñata that has been filled with a fresh batch of catnip and assorted kitty toys.

Márquez is not unaware that his largesse may appear odd, or even irresponsible to some. “It seems like a lot of money to spend on your cat. But when you live with an animal, you start to think of her as a member of your family, not as something you own,” explains the self-described bachelor. Still, he took heed of criticism from friends who thought it unseemly for him to spend several thousand dollars on a party for his infant cat.

“I know they have a point,” Márquez concedes, “that’s why my other present to Mus-Mus is a donation in her name to a local battered-womens shelter. She got a letter from them acknowledging the gift and everything. After all, Mus-Mus herself was once a stray.”