For more than two decades, Kentucky Sen. Rand Paul was a member of a group, the Association of American Physicians and Surgeons, that advocated a link between vaccinations and autism, among other conspiracy theories.

The AAPS, as Kentucky's Courier-Journal noted in a 2010 article on Paul's association with it, opposes mandatory vaccinations and promoted discredited studies, which linked the vaccine-component thimerosal to autism in children.

"Mandatory vaccines violate the medical ethic of informed consent. A case could also be made that mandates for vaccines by school districts and legislatures is the de facto practice of medicine without a license," the group said in a fact-check.

Paul's adviser, Doug Stafford, told BuzzFeed News he didn't know if Paul was still a member of the group but that he joined because it was a group of pro-life doctors. He said Paul does not endorse all the group's views.

Jane Orient, who handles media for AAPS, said she did not believe Paul had renewed his membership.

A statement of the group's principals on its website says it's "evil" and "immoral" for doctors to participate in Medicare.

The AAPS journal also published a study by David and Mark Geier linking vaccines to autism, and has questioned the link between HIV and AIDS.

The group's about page features a video of Paul on Fox News talking about a lawsuit by the AAPS arguing that health care reform was unconstitutional. He has spoken about the group before in public as well.

"I use a lot of AAPS literature when I talk," said Paul addressing the group in 2009, noting he'd been a member since 1990.

In March 2013, the group issued a press release congratulating the longtime member for his win in a presidential straw poll.

"When Dr. Rand Paul was running for Senate in Kentucky in 2010 — and was supported by AAPS PAC — the press tried to smear him based on his membership in AAPS. But Dr. Paul did not back down or apologize, and he won in a stunning landslide," the group said in a press release.

In 2010, Paul's campaign said he was a member of the group because they supported market-oriented health care reform.

"Dr. Paul is member of AAPS because they believe that any health care reform should be market-oriented and embrace more freedom, not more government," Jesse Benton, Paul's campaign manager, told the Courier-Journal in 2010.