The declining U.S. birth rate has dogged baby-care marketers since the recession began in 2007. Now Kimberly-Clark Corp.'s Huggies and its agency, Ogilvy, Chicago, have decided to do something about it: Create a Huggies Baby-Making Station on Pandora for Valentine's Day, playing tunes aimed at getting couples in the mood.

Think of it as a digital-age millennial version of the old make-out tape, replete with entries from Barry White and heavy on other R&B classics, including Stevie Wonder's "My Cherie Amour."

Millennials clearly need all the help they can get. The U.S. birth rate fell to 62.5 per 1,000 women ages 18 to 44 in 2013, the last year for which data is available, from 69.3 in 2007, according to the Centers for Disease Control (maybe lumping pregnancy in with disease control is part of the problem). Recent increases in birth rate among women over 30 have been too small to offset the decline among women under 30.

"I've been working on Huggies for five years, and one thing we're always dealing with, project after project, year after year, is the declining birth rate," said Chris Turner, group creative director at Ogilvy, Chicago. "Lately, we've been thinking about Valentine's Day as an agile opportunity, and we kind of put the two together."

"At Huggies, babies are always on our mind," said K-C spokesman Bob Brand. "The partnership with Pandora is a fun-loving way to engage Huggies couples in the romantic spirit of Valentine's Day."

The Huggies station will play without commercial interruption on Pandora for at least a month, backed by ads on other Pandora stations and by social-media efforts through the brand's accounts, Mr. Turner said.

Valentine's Day was once the province mainly of jewelers, chocolatiers, florists and condom brands (maybe another part of the birth-rate problem). But Huggies is the latest non-traditional packaged-goods brand to jump on the holiday's bandwagon, following a publicity effort from Clorox 2 featuring celebrity sex therapist Dr. Ruth.