Booking.com, one of the world’s largest accommodations booking sites, surveyed 21,500 travelers this summer about their dream trips, and 40 percent reported that they wanted to take or had actually taken a trip based on the results of home DNA tests.

Allegra Lynch, a member of the Travel Leaders Network who lives in Santa Rosa, Calif., said that she sold $1.5 million worth of such trips in 2018, primarily to Europe, compared with $800,000 in 2017. “The rise is 100 percent because of people wanting to go on trips after taking at-home DNA tests,” she said.

An online video created for AeroMexico by the Ogilvy advertising agency last year played on the trend, offering discounts to Americans to fly to Mexico based on the portion of their heritage that a DNA test determined was from Mexico. Amid the debate around border security, the ad has recently gone viral on the Internet. John Raul Forero, the chief creative officer for Ogilvy Latam confirmed in an email that the ad had been created last year for the airline but had no further comment. The DNA promotion is no longer valid, according to Paula Santiago, a spokeswoman for the agency.

Although some genetic experts question the accuracy of such tests to pinpoint geographical ancestry, the molecular genealogist Diahan Southard said that the results are usually on the mark, save for some exceptions. “The ethnicity breakdown you receive from a testing company relies heavily on the people the company is comparing you against,” she said. “If you are from France, but your company hasn’t tested very many French people, they aren’t going to do a very good job with your breakdown.”

Still, accessibility and affordability are helping DNA-based travel take off, according to Sarah Enelow-Snyder, an assistant editor at the travel research company Skift. “You can buy one for less than $100, and it’s a price that has helped propel the popularity of these trips,” she said.