Editor's Note: (Watch "United Shades of America," Sundays at 10 pm ET on CNN.)
(CNN) Dallas resident Stephanie Houston was driving from the store with her teenage son one day six years ago when he blurted out words that changed their lives forever.
"Oh by the way," Pierre, then 17, told his mom. "I'm going to live my life as a woman now."
Houston was stunned, but she maintained her composure and tried to keep her eyes on the road.
"I almost wrecked my car. I said, 'Well, how the hell are you going to do that?'" she told W. Kamau Bell, host of the CNN original series "United Shades of America," which explores the challenges facing Black trans women in Sunday's episode.
Soon after, Pierre became a transgender woman named Muhlaysia Booker. In April 2019, she was attacked by a man in the parking lot of a Dallas apartment complex as some people shouted anti-gay slurs, an incident captured on cellphone video.
A month after that, she was shot dead in the street. She was 23.
Booker's slaying is part of a disturbing trend. Activists say deadly violence against transgender and gender-nonconforming people has risen in recent years, and many of the victims were transgender Black women.
Booker was one of at least 27 transgender and nonconforming people killed in 2019 in the US, according to the Human Rights Campaign. Of those, at least 21 were Black transgender women.
Last year, in the middle of a pandemic, at least 44 transgender or gender-nonconforming people were killed in the US -- the highest number since the Human Rights Campaign started tracking data in 2013. Of those, about half were transgender women of color, a majority of them Black.
So far in 2021, the HRC has counted at least 28 transgender or gender nonconforming people killed, the highest number it's recorded at this point in the year. At least 20 of them were Black or Brown trans women, said Alphonso David, president of the HRC, who added that the number of victims is likely higher because many such attacks go unreported or misreported.
"Fatal violence disproportionately affects transgender women of color because they are at the intersections of racism, sexism, homophobia, biphobia, transphobia," David told CNN. "And they, unfortunately, are receiving the brunt of the violence in this country."
Houston recalls the day in May 2019 she got the call that her daughter had been shot dead.
"I had so much anger. I just kept trying to make sense of it," she said. "Muhlaysia would tell me all the time (that) ... she was willing to die for her respect and her transition."
Before her death, Booker's fight for respect tested their relationship in unexpected ways.
Houston shared an example from her daughter's 18th birthday party, shortly after their argument in the car. Houston was hosting the party at their home when Booker walked in, wearing women's clothes for the first time in front of her mother.
"I engaged for a little while and then I had to go lay down because it was too much for me," she said. "I come from a Christianity background. That's taught to be wrong. And as a parent, I didn't know who to talk to. This is just stuff you don't talk to people about."
But Houston said she also noticed something different about her child. She was no longer the quiet and timid Pierre. As a transgender woman, her daughter was confident, expressive and full of life. She held video sessions on Facebook Live, where fans tuned in to hear her talk about everything from lipstick shades to her braids.
"She had this thing where she said, 'mom, you gotta start calling me Muhlaysia.' And I'm like, 'no -- Pierre.' And she would always be like, 'Ew, that punk, I don't like that punk, that boy,' " Houston said. "Muhlaysia gave her this boost ... this confidence."
Houston described having an initial tug-of-war with her daughter over her new identity, which led to Booker avoiding coming home. But Houston missed her daughter and eventually persuaded her to come back.
"I started yielding. And I said, 'OK, if you want to be Muhlaysia, I'll call you Muhlaysia'," Houston said.
By then, Booker was part of the local transgender community and even had a bonus trans mother, Tatiana Specks, from the LGBTQ family she'd found outside her home.
"I saw the leader in her. She wasn't a follower," Specks tells Bell in this week's episode of his CNN show. "I was intrigued by her. I wanted to get to know her."
While there's no comprehensive data, David said an estimated 2 million people in the United States identify as transgender or nonbinary -- a gender identity that can't be categorized as exclusively male or female.
Many transgender people have difficulty living full and open lives because of dehumanizing abuse and fear of being assaulted, David said.
"This is very real for people, because if you are afraid of leaving your home at night, or walking home, or walking to the store, you're really not free," he told CNN. "If you are transgender, if you're Black or Brown, because most of these deaths are Black or Brown transgender and gender nonconforming people, you are not able to exercise your freedom in this country."
These fears have been compounded by a flurry of recent legislation that advocates say discriminates against transgender people.
So far this year 33 states have introduced more than 100 bills that aim to curb the rights of transgender people across the country. Advocacy groups say 2021 is on track to be a record-breaking year for such legislation.
In Arkansas, for example, legislators in April passed a law that prohibits physicians in the state from providing gender-affirming treatment for trans youth. A similar bill died in the Texas House in May, though Texas Gov. Greg Abbott may seek to resurrect it.
And earlier this month Florida became the eighth state this year to enact a ban on transgender girls and women in public secondary schools and colleges from participating on girls' and women's sports teams.
Advocacy groups are concerned such laws could lead to more attacks on trans women.
But even with these legal setbacks, transgender people in the US have had some recent wins, David said.
In April President Biden pledged support for transgender Americans during his address to a joint session of Congress.
And public acceptance of LGBT Americans appears to be growing.
More than 70% of the American public now supports equality and nondiscrimination protections for LGBTQ people, and more than two thirds oppose anti-LGBTQ bills, said David of the HRC. Every election brings more voters who support equality, he said.
"We're seeing an increase in the number of people who support equality each and every year," he said. "So we are winning. What you're seeing is a backlash."
Since Booker's death two years ago, her mother has turned her grief into action.
Houston launched the Muhlaysia Booker Foundation, where families with transgender children can go for guidance and support.
"A lot of people have been beaten, killed. So mama's gonna take the baton and turn it into something positive," she said. "I thought about some of the times when we would get into it, and I was glad she wasn't alone. She can go cry to somebody who she felt understood her ... she could go and be with her extended family."
Booker's death hit close to home in Dallas' community of Black trans women and gender-nonconforming people. In response they created the House of Rebirth, which provides sanctuary for Black trans women along with such services as career training, counseling and study groups.
Houston is hoping to use her platform to honor her daughter's memory. At Booker's funeral, she asked members of the trans community to stand and recognized them as her daughter's extended family. She singled out Specks, and told the crowd that she'd played a major role in her daughter's life.
Houston wants people to know she loved and accepted her daughter. And she's working every day to make sure her legacy lives on.