"How are all black men not crazy at this point? How have they not been driven insane by racism?"

This was the unexpected lesson that Kortney Ziegler, a black transgender man, learned after he transitioned to presenting as a man. He'd experienced racism when he presented as a woman — but he found himself facing considerably more suspicion as a man.

"People are visibly uncomfortable around me," he said.

Lily Carollo had a parallel experience with her transition. Presenting as a woman made her experience street harassment on a daily basis for the first time — something she didn't have to deal with when she presented as a man. As a result, she said, she's turned into a "feminist firecracker."

When I asked trans activists about these stories, they weren't surprised. "I think it shows you how society is," Mara Keisling, executive director of the National Center for Transgender Equality, said. "American society is a different place for black men compared to black women, and women compared to men generally, and people of color compared to white people generally."

Many people know that sexism and racism are problems in America. But transgender people — whose gender identity doesn't match the sex assigned to them at birth — have the opportunity to experience the full range of these issues firsthand. For some trans people, then, sexism and racism aren't just abstract issues that are present in the news or studies — they're issues they can validate with their personal experiences living on both sides.

"The more time I spend as a woman, the more of a feminist firecracker I become"

Carollo, a trans woman, said she underestimated sexism when she presented as a man. As a self-described liberal, she was aware of gender issues, like street harassment and workplace inequality, before her transition. But presenting as a woman forced her to confront the problems firsthand — and dramatically heightened her awareness of the objectification and sexism women face just by going out for a walk.

"The more time I spend as a woman, the more of a feminist firecracker I become, and more involved with women's issues," Carollo said. "It really shocked me when I transitioned and started passing as a woman how differently women are treated in society compared to men."

She added, "Preparing to go out on a walk around the block in a city or in a downtown area, I now worry about whether I'm alone and whether it's dark and whether I'm safe. And even if men don't street harass, there's a lot of leering. Even if I stare at them back with a look that's asking them what the fuck they're doing, they continue to stare at me. It bothers me. Stop staring at me!"

Street harassment is a problem many women are already familiar with. Particularly in major cities, some women can't go through the day without hearing unsolicited comments about their looks and other forms of catcalling.

In 2014, Hollaback, an organization that wants to end street harassment and intimidation, produced a video in which a woman walked through New York City for 10 hours. The hidden video camera placed in the backpack of a man walking in front of her recorded more than 100 instances of verbal harassment. After the video went viral, the woman in it received rape threats on YouTube.

As Kelsey McKinney explained for Vox, the video's story revealed several layers of discrimination: "Women are forced to feel uncomfortable and scared for walking down the damn street. Then when one woman takes the time to show just how uncomfortable those interactions are, people threaten to physically assault her. If the video reminded us that women are constantly made to feel unsafe when they leave the house, the response is a reminder that women are constantly made to feel unsafe when they simply turn on their computers."

Carollo's story echoes these concerns: Instead of feeling safe when she goes out, she worries about men leering at her or doing something much worse.

"I'm always considered to be stealing things"

Ziegler, a trans black man in Oakland, California, said he was mistreated because of his race when he presented as a woman. But after his transition, he said the type of racism he faces has completely changed in a way that's more visible and direct in his life.

"People police me a lot more than they did before — by that, I mean literally police," he said. "People feel they can touch me more without my consent. I'm physically stopped a lot. People are visibly uncomfortable around me. I'm always considered to be stealing things."

He added, "A lot of my work is in the tech industry, where there's not a lot of black men. I was recently going to an event here in Oakland that was held by a private group. I walked in the place, and this woman literally grabbed me, stopped me, and said, 'This is a private event. You're not supposed to be here.' Those things happen to me all the time. People always tell me I'm not supposed to be in places without even asking me."

Over the past few years, the systemic racism black men face has received a lot of attention in media. The August 9, 2014, police shooting of Michael Brown in Ferguson, Missouri, highlighted not just the racial disparities in the Ferguson Police Department and court system, but also the disparities black people face across the country. A ProPublica analysis of the available, limited FBI data found black teens were 21 times as likely as white teens to be shot and killed by police between 2010 and 2012. And an analysis of the same data by Vox's Dara Lind found that US police kill black people at disproportionate rates: Black people accounted for 31 percent of police shooting victims in 2012, even though they made up just 13 percent of the US population.

One of the causes of these disparities is subconscious racial bias. Josh Correll, a University of Colorado Boulder psychology professor, has run video game simulations to verify that some of these biases are present among police officers. But his findings also show that these biases are even more pronounced among the general public, which doesn't receive the kind of racial sensitivity training that cops do.

The subconscious biases are what lead even well-meaning people to, for example, guard their purses or take the next elevator when a black man is around. It's perhaps how someone at a professional convention in liberal California can feel okay grabbing Ziegler and telling him to leave without even asking for ID.

This is such a widely known problem in black communities that there are social media accounts dedicated to it. Vine user Rashid Polo produced a series of videos of people following him around the store:

But for someone who's experiencing this type of discrimination for the first time in adulthood, it's shocking.

"It's a whole new experience," Ziegler said. "I think that's the major focal point of my transitional journey: how to remain sane living in this world that discourages black masculinity so much."