The gap in opinion between young and old in the U.S. can often be wide. The country has seen significant movement on political issues such as gay marriage and marijuana legalization in recent years, much of it due to the entrance of younger people on the political scene.

Now it appears that American opinions on animal rights are set to change dramatically in the coming years as well. New research presented at the annual meeting of the American Association for the Advancement of Science this week has shown that more Americans are now opposing medical testing on animals.

The study, performed by researchers from Western Governors University and People for the Ethical Treatment of Animals (PETA) looked at survey data from Gallup between the years 2001 and 2013. They found that 41% of U.S. adults said they oppose animal medical testing in 2013, a 12% increase over 2001 opinion levels.

What’s most interesting about the data, though, is how different various demographic groups’ opinions on the matter were. Only around 33% of Americans age 30 and older last year said that they oppose medical testing on animals. Meanwhile, over half (54%) of adults age 18 to 29 oppose animal testing, a full 23% increase over that statistic as measured in 2001.

The data also shows a significant gender gap when it comes to animal testing. In 2013 52% of U.S. women said they oppose animal testing versus only 30% of men.

“Opposition to animal testing is steadily rising among people of every gender, age group, and political affiliation, likely because people have more exposure than ever to information about the cruelty that animals endure in laboratories, how animal testing rarely helps humans, and the superior alternatives available,” said Justin Goodman, co-author of the study and a director at PETA. “Now, the country’s laws and policies governing animal experimentation and its research funding practices need to evolve to meet public expectations as well.”