Kohler has sold conventional bidets in the United States since 1928. Its marketing for the C3 has been more restrained than Toto’s, and has involved avenues that are unlikely to jar a customer’s sensibilities, like showroom displays and DVDs, said Shane Allis, a product manager for the company. (“Our consumers have been using paper for a very, very long time,” he explained.)

But Kohler, too, feels it is a good time for the seats to take off, for the reasons Ms. Campos gave and because of a growing desire to see bathrooms as spa environments. The C3, he suggested, “offers that luxurious experience that consumers are wanting to have in all areas of their bathrooms.”

There is evidence that Americans have generally become more comfortable with bidets. The National Kitchen and Bath Association kept statistics on bidets for the first time in 2006, and Ed Pell, the group’s manager of market research, said that of the 5.3 million bathrooms built in the United States that year, more than 650,000 included one.

Image MR. BIDET Arnold Cohen displays his own bidet seat at a trade show in 1964.

Janice Costa, the editor of Kitchen & Bath Design News, said she started seeing bidet seats at kitchen and bath shows in the last two years. She believes they will catch on within five years as a high-end trend that may eventually broaden. “The toilet is the last bastion that has not been luxurified,” she said. “People are looking to upgrade every aspect of their lives, and the toilet is the last to be touched.”

The bidet seat offers advantages over the traditional bidet, particularly in markets like New York City, where bathrooms do not have the space for an additional fixture. Even when space is not an issue, installing a traditional bidet “can’t be done without going through major renovations,” said David Esbin, the manager of the plumbing and hardware division of Manhattan Center for Kitchen and Bath.

The bidet seat, on the other hand, can be installed without reworking the plumbing (although it does require an electrical outlet, which can cost as much as $500 to install). Toto’s and Kohler’s models cost $700 to $2,200, but those prices are low compared with the cost of a traditional bidet and the contracting work required to install one.