At a rally hours before pro-Trump demonstrators assaulted the U.S. Capitol, Donald Trump Jr. on Wednesday attacked transgender women athletes in an expletive-laden speech.

After thanking attendees for “being in this fight with us” and “standing up to the bull----,” Trump said "amen and a-woman," sarcastically referring to how Rep. Emanuel Cleaver, D-Mo., ended the first daily prayer of the new Congress on Sunday.

He then used that remark to pivot to a recent study that found transgender women retain an athletic advantage over their cisgender peers even after a year of hormone treatment.

“That shows you the mentality of where the Democratic Party is,” said Trump, who also retweeted NBC News’ article about the study. “They spent money on a study that came to the incredible conclusion yesterday that trans women playing female sports have a competitive advantage.”

“No s---!” he yelled. “Who could have seen that coming?”

At that point, Fox News, which had been covering the rally, cut off the feed and returned to anchor Sandra Smith, according to a clip captured by Daily Beast editor Justin Baragona.

A report in the British Journal of Sports Medicine showed transgender women were able to do 10 percent more pushups and 6 percent more situps in the first two years after starting estrogen and testosterone blockers.

The study’s lead author, Timothy Roberts, denied that the Democratic Party, or anyone else, had funded the report. “This was done in addition to our normal duties as a service to our patients” he said.

Roberts and his colleagues gathered data by reviewing existing medical records and fitness test evaluations of U.S. Air Force members who started or continued transition-related treatment while still in service.

Current International Olympic Committee guidelines require transgender female athletes to be on testosterone blockers for at least a year before entering competition, but Roberts said that may be inadequate.

“For the Olympic level, the elite level, I'd say probably two years is more realistic than one year,” he told NBC News previously. “At one year, the trans women on average still have an advantage over the cis women. They just do.”

He added that a one-year waiting period was sufficient for student athletes and nonprofessional leagues.

“There's a whole lot of people playing recreational sports, and very few people get to be pros, so just let them play,” he said.Roberts said he was flattered that Trump Jr. chose “to recognize and promote our work.”

“I encourage everyone to read the article for a more nuanced view of our findings," he added.

At the rally, Trump Jr. also complained about the U.S. giving “$10 million to Pakistan on gender studies … and billions elsewhere that is driven by the insanity of the left.”