GEOFF BENNETT: The U.S.

Supreme Court began a new term today marking the first day of oral arguments.

One of the marquee cases of this term will be argued tomorrow, a challenge to a ban on so-called conversion therapy for youth.

The practice broadly refers to attempts to change a person's sexual orientation or gender identity.

It's banned in 23 states and the District of Columbia.

By one estimate, some 350,000 LGBTQ adults received conversion therapy as adolescents.

The Supreme Court declined to hear challenges to such bans in the past.

But, as Stephanie Sy reports, this case is being heard against a backdrop of intensifying cultural and political debates around LGBTQ rights.

And a warning: The story includes discussion of suicide.

KALEY CHILES, Licensed Professional Counselor: And then every step you take.

STEPHANIE SY: Kaley Chiles has been a licensed counselor in Colorado Springs for about 10 years.

Her clients are mostly adults, but she sees some families and adolescents too.

And sometimes clients seek her help specifically because she's Christian.

KALEY CHILES: That is the world view on which all of my other activities lie.

And so that's just going to be an inevitable part of anybody coming and talking to me.

I meet them and we have a conversation.

What goals, if they already have goals in mind, do they think counseling will help them accomplish.

STEPHANIE SY: But, right now, Chiles says, the state of Colorado prevents her from helping some clients reach their goals.

In 2019, Colorado passed a law banning treatment for those under 18 that -- quote -- "attempts or purports to change an individual's sexual orientation or gender identity, including efforts to change behaviors or gender expressions or to eliminate or reduce sexual or romantic attraction or feelings toward individuals of the same sex."

Licensed providers who violate it face a $5,000 fine and potential loss of their license.

This week, the Supreme Court is hearing a challenge to Colorado's ban.

The lawsuit backed by the Trump administration was brought by Kaley Chiles, who argues the ban infringes on her right to free speech.

KALEY CHILES: The only care that we're talking about is conversations with people who are voluntary and who are coming to my office because they want to see me.

The care that is at stake in this lawsuit is that we are allowed to speak freely and that we are allowed to, by the product of that, sort through feelings, sensations, thoughts, beliefs.

It's truly that we can have a conversation without the government peering into our private counseling conversation and dictating what we can and cannot talk about.

STEPHANIE SY: Supporters of the ban say it's not a question of free speech, but professional conduct, regulating health care by prohibiting a practice that research has shown to be not only ineffective, but also associated with a roughly two-fold increase in suicide attempts.

JOYCE CALVO, Mother of Alana Chen: Yes, so this was in Spain.

STEPHANIE SY: Joyce Calvo's daughter, Alana Chen, was a devout Catholic who wanted to become a nun.

But when she was just 14, Chen confessed to a priest that she was attracted to other girls.

JOYCE CALVO: He went on to tell her that was a mortal sin, which is the worst sin.

And it's very scary for a child to think they're going to burn in hell.

And he was just telling her all these books to read and that I can help you.

And she was afraid, so she wanted that help.

STEPHANIE SY: After her confession to the priest, Calvo says Chen received almost a decade of conversion therapy and religious counseling, hidden from her parents.

Chen later described her experiences and emotions in her own words.

JOYCE CALVO: "I think the church's counsel is what led me to be hospitalized.

I was feeling so much shame that I was comforted by the thought of hurting myself."

STEPHANIE SY: Chen died by suicide in 2019, when she was just 24.

WOMAN: I didn't want anyone to know why I loved God so much.

STEPHANIE SY: Her story was documented in the podcast "Dear Alana" hosted by Simon Kent Fung, who experienced years of conversion therapy himself.

SIMON KENT FUNG, Host, "Dear Alana": It ends up stacking on levels of shame that a lot of people never recover from.

First, there's the shame that you feel for just being different, right?

Then there's the shame that comes from being told that something horrible happened to you that may do this way.

And then, thirdly, there's the shame that happens when you can't actually change.

STEPHANIE SY: Colorado's law doesn't apply to unlicensed religious counselors such as priests, who account for the vast majority of conversion therapy cases.

The ban went into effect just months before Alana Chen's death.

This past August, Calvo filed an amicus brief with the Supreme Court.

JULIA SADUSKY, Clinical Psychologist: How does my faith inform and fit with these experiences?

STEPHANIE SY: Julia Sadusky is a clinical psychologist in suburban Denver.

A Catholic, she often works with Christian youth and adults who struggle with their sexuality or gender.

She too wrote a brief for the Supreme Court case.

If a gay patient comes in or a transgender patient comes in and says, "I don't want to be this anymore," can a clinician set that goal and be within the ethical sort of framework that you all have as licensed practitioners?

JULIA SADUSKY: Therapy is not just about talking.

It's about psychological interventions that have research behind them.

When my clients come in and they do want to change their attractions, let's say, or they do, they want to align with their sex, it's not that as a therapist I'm arbitrating that and I'm saying, you're not allowed to have that goal.

What I'm doing is, I'm bringing in what we know from research.

And what I can tell you from the research is, we do not have clear protocols that help people align with their sex, and we don't have clear protocols that have been effective in changing sexual orientation.

STEPHANIE SY: Sadusky also argues that the ban doesn't actually prohibit the kinds of conversations Kaley Chiles wants to have with her clients.

JULIA SADUSKY: To the credit of whoever drafted this law, they wrote into the law that you are allowed to help people with identity exploration and identity development.

I don't know how much more clear a law could be about the valuing of identity work, the valuing of exploration without having a fixed outcome.

STEPHANIE SY: But some disagree.

ERIN LEE, Colorado Mother: It's very explicit that this is a requirement of the law that you cannot do anything but affirm or ignore.

And that's my experience.

STEPHANIE SY: In Northern Colorado, Erin Lee says her daughter Chloe began abruptly questioning her gender identity several years ago.

ERIN LEE: We didn't know how to talk about it.

And we didn't want to say anything we couldn't take back.

And so we just totally ignored it.

We didn't affirm, so we didn't call her the new name.

We also didn't say, you're not trans, that's not real.

STEPHANIE SY: Lee eventually contacted multiple therapists, but couldn't find the right fit.

ERIN LEE: We found a Christian counselor.

We were not Christian at the time, but we were looking for someone who wasn't going to automatically affirm.

She went through like six of these sessions and she was getting worse mentally.

She was becoming more withdrawn, more dark.

And we thought, why isn't she getting better?

But I now understand it's because counselors didn't -- they're afraid.

They're afraid to touch this issue.

They know they can't do what they're trained to do, which is ask questions and get to the root cause of why this person's feeling that way or help them through it.

In our daughter's case, she didn't want to feel that way.

STEPHANIE SY: Chloe, who is now 16 and no longer identifies as a boy, has since spoken out about her experience.

KALEY CHILES: I can certainly think of adolescents and people who I have witnessed suffer from this law.

STEPHANIE SY: Back in Colorado Springs, Kaley Chiles says she's had to turn away clients because she believes the law forces her to avoid certain conversations.

KALEY CHILES: The consequence is a $5,000 fine and the loss of your license, which is the loss of your career and your livelihood.

That's not a risk many people are willing to take.

STEPHANIE SY: Colorado officials say they haven't taken action against any provider since the law took effect.

But if the High Court overturns the ban, its supporters, like Joyce Calvo and Simon Kent Fung, believe the impacts will be sweeping.

SIMON KENT FUNG: I think the tragic outcome of this is likely that we're going to see more kids feeling alienated from their families and despairing.

What we're likely going to see are more stories like Alana's.

STEPHANIE SY: Alana eventually realized the conversion therapy wasn't working and her writings took on a different tone.

JOYCE CALVO: "I always thought there must be something wrong with me, not wrong with God or his roles.

I feel like I have been fooled all this time.

I'm so angry.

I'm hurt.

I still feel broken."

STEPHANIE SY: By then, it was too late.

Her faith and her life were lost.

For the "PBS News Hour," I'm Stephanie Sy in Colorado.