A senior adviser at the Democratic National Committee, Zak Petkanas, could not name one scientist on Thursday night who would back his views on transgender individuals.
Petkanas, head of the DNC's "war room" targeting President Trump, appeared on Fox News with host Tucker Carlson to discuss Trump rolling back much of former President Barack Obama's guidelines that allowed transgender students to use bathrooms that matched the gender they identify with.
Carlson asked Petkanas to name one scientist who could explain how an individual can choose their sex and the role of the federal government in the issue.
"This is a matter of settled science," Petkanas said, appearing to dodge Carlson's question.
Petkanas also called Carlson's views on transgender issues "right-wing pseudoscience."
Carlson then asked Petkanas to name a scientist who would defend his position.
"I will give you a thousand dollars if you can find any scientist, like an actual biologist at an accredited American college, willing to come onto this show and say, 'Here's the science,'" Carlson said.
As he closed out the segment, Carlson again challenged Petkanas to produce a scientist who would defend his position that one could choose their own gender.