CREDIT: AP Photo/J. Scott Applewhite

Before failed presidential candidate Ben Carson spoke at the Republican National Convention Tuesday night, he spent much of the day railing against transgender people. His latest quip is to suggest that being transgender is like deciding one day to be a different race.

Speaking to the convention’s Florida delegation Tuesday morning, Carson insisted that biology trumps gender identity:

You know, we look at this whole transgender thing. I got to tell you: For thousands of years, mankind has known what a man is and what a woman is. And now, all of a sudden we don’t know anymore. Now, is that the height of absurdity? Because today you feel like a woman, even though everything about you genetically says that you’re a man or vice versa?

Wouldn’t that be the same as if you woke up tomorrow morning after seeing a movie about Afghanistan or reading some books and said, “You know what? I’m Afghanistan [sic]. I know I don’t look that way. My ancestors came from Sweden, or something, I don’t know. But I really am. And if you say I’m not, you’re a racist.” This is how absurd we have become!

Carson went on to say that he’s “disturbed” that “secular progressives” are discussing transgender issues in terms of civil rights. “We have to be willing to call out people for this absolutely ridiculous stuff that they’re trying to put over on us, that they’re trying to put over on our children,” he said.

In an interview later that day with Katie Couric, Carson doubled down on these remarks, repeating his Afghani/Swedish metaphor and reasserting his belief that gender identity is prescribed by genetics just like a leopard’s spots:

It is silly for us to engage in something that we have known for thousands of years. We have known what a man is and what a woman is for thousands of years. All of a sudden, we don’t know anymore. I said that is absurd. […] There are biological markers that tell us whether we are a male or a female, and just because you wake up one day and you say, ‘I think I’m the other one,’ that doesn’t change it. Just — a leopard can’t change its spots.

When Couric pushed back, Carson insisted that the way people feel doesn’t change who they are and doesn’t change their genetics. When asked if there should be tolerance for transgender people, he demanded that tolerance “goes in both directions.” Transgender people don’t deserve “extra rights,” he said, because “nobody gets to redefine everything for everybody else and then make them comply to it. That’s not tolerance.”

Carson isn’t wrong that biology is a factor, but he is wrong that it disproves transgender identities. Indeed, it does the very opposite. Researchers at Boston University reviewed the available research and found significant evidence that there is a biological basis for being transgender. Studies have identified differences in sexual development, brain structure, and hormone genetics unique to transgender identity.

As Couric tried to point out, transgender people do not wake up one day and decide to be a different gender, as Carson suggested. The increasing number of young children who feel comfortable coming out as transgender indicates that this is not an experience spurred by something like watching a movie or reading a book. Research on these kids is finding that their gender identities are just as consistent as their cisgender peers, and their mental health benefits when those identities are affirmed by their families.

Carson’s comments Tuesday were not out of character. He has previously suggested that allowing transgender people to use the bathroom amounts to granting them “extra rights” at the expense of others’ “comfort.” Allowing trans people to serve in the armed services, he has said, would treat the military “as a laboratory for social experimentation.”

And he’s hardly alone. The 2016 Republican Platform takes similar aim, calling policies that respect trans identities “alien to America’s history and traditions” because they are “illegal, dangerous, and ignore privacy issues.”