Although self-driving cars are becoming more of a reality each day, the majority of Americans are wary of the idea, according to a Reuters/Ipsos poll.

When asked whether they felt comfortable with the notion of “riding in an entirely self-driving car,” a whopping 67 percent of Americans said they were “not comfortable.” Only 27 percent said they were “comfortable” with the idea.

Males were significantly more likely than females to be on board with the idea, with 38 percent of men saying they were comfortable with the idea. That’s compared to just 16 percent of females.

Perhaps unsurprisingly, millennials were the age group most likely to embrace such technology. Some 38 percent said they would be comfortable with the idea, compared to 27 percent of Gen-X respondents. Just 16 percent of baby boomers said they’d be comfortable with self-driving cars on the roads.

The survey comes as automotive and technology executives are pushing American lawmakers to pass legislation that would loosen restrictions on testing and deploying self-driving cars. Meanwhile, companies including General Motors and Alphabet Inc’s Waymo are aiming to release the first wave of self-driving cars. GM’s self-driving Chevrolet Bolt – which doesn’t contain pedals or a steering wheel – is set to become the first production-ready car without the tools necessary for human control by 2019.

GM is currently applying for permission from the federal government to run the test cars without a driver. However, current US regulations require vehicles to have controls for drivers, unlike the Bolt. Even if the government approves GM’s petition, the company will still need to get permission from individual states to legally run them.

Russia’s Yandex has also jumped aboard the self-driving car frenzy, taking its autonomous Prius car for its first journey in the snow in November. The car successfully drove 300km (186 miles) in wintry weather conditions.

The Reuters/Ipsos poll was conducted between January 11-18 and collected responses from 2,592 adults.