JOHN YANG: According to the advocacy group the Human Rights Campaign, half of the states in America have passed laws or policies restricting treatment for young people diagnosed with gender dysphoria.

That's the discomfort or distress that might occur when someone's gender identity differs from their sex assigned at birth.

Some of those laws are on hold while court challenges work their way through the system.

The legislative debate on these measures has often been long on emotion, but short on science and medicine.

A new book seeks to use science and research to explain gender identity and treatments for transgender youth.

It's called "Free to Be: Understanding Kids and Gender Identity."

The author is Dr. Jack Turban.

He's the founding director of the Gender Psychiatry Program at the University of California, San Francisco.

Doctor Turban, thanks for joining us.

Let's begin with sort of the basics.

Gender identity, sex assigned at birth, what do they mean, and how can they be different?

DR. JACK TURBAN, Author, "Free to Be: Understanding Kids and Gender Identity": So gender identity is your psychological sense of yourself in terms of masculinity and femininity.

It's extraordinarily complicated, right?

We know from research that there is a biological basis of how we think about ourselves in terms of gender, but then we interact with society and culture to create this really complex understanding of who we are and how we think about ourselves.

Sex assigned at birth, also unfortunately complicated.

It could be based on your chromosomes, based on different sex organs.

But generally, there are these biological characteristics that end up being on your birth certificate.

And then -- so when I say sex assigned at birth, I'm usually referring to what's on someone's birth certificate.

JOHN YANG: And when they conflict, what happens?

JACK TURBAN: Yeah.

So, for most people, their gender identity aligns more or less with their sex assigned at birth.

But a lot of my patients, there's a misalignment, and so they may identify as transgender or gender non binary, which just means that they have a sense of themselves that doesn't align with their sex assigned at birth.

For some of those kids, they have really intense gender dysphoria, where there's distress related to their body not aligning with their gender identities.

For other kids, they don't have so much distress about their body.

And so the big thing I try and explain in the book is just this nuance of what gender related experiences are like and what those experiences are like for all different kids.

Early on in the book, you quote an endocrinologist named Dr. Norman Spack, who's sort of a leader in this field, as saying being transgender isn't a condition of the brain, but of the body.

Explain that.

JACK TURBAN: Yeah, so he's an endocrinologist.

I'm a psychiatrist.

We think about it a little bit differently.

The way he thinks about it is that their body has betrayed them, essentially, that their gender identity is who they are, and that's what's important.

And the endocrine interventions that he offers for some young people are meant to align the body with the gender identity that he thinks is really the core of who those people are.

JOHN YANG: And having said that, what are the implications of that for treatment of young people who are transgender?

JACK TURBAN: The way in reality we approach these kids is they have a comprehensive mental health evaluation to really understand their gender history, what other mental health conditions they may have, and also understand their relationship with their physical bodies for some of these young people, but not all, they might be candidates for certain medical interventions.

So things like puberty blockers or gender affirming hormones like estrogen or testosterone.

JOHN YANG: Now, a lot of these laws that have been passed in the states limit treatments on transgender minors, young people, they say that they're trying to protect them.

You're saying they're actually harming them.

Explain them.

JACK TURBAN: So, for a lot of these kids, these are really important interventions that improve their mental health.

So I have patients who become severely depressed and anxious when their bodies start developing in a way that doesn't align with their gender identity.

And we have more and more research studies showing that when we offer these kids relief with these interventions, that their mental health is a lot better.

So unfortunately, these bills just ban the treatment altogether so that none of the kids can access these treatments that we see help them.

JOHN YANG: A lot of the supporters.

These bills also point to Europe, where some countries are banning puberty blockers, other treatments.

There's a pediatrician in Britain named Hilary Cass who was commissioned to review the scientific data on this, and she said it was remarkably weak.

What do you say to that?

JACK TURBAN: I think a lot of people don't realize the nuances that were in that document.

In a lot of ways, it actually agrees with how we practice care in the United States.

So it recommended that you should do a comprehensive mental health evaluation before starting these interventions.

They should have a holistic view of the young person to understand if there are both medical and nonmedical interventions that might be appropriate.

The big area of divergence between her report and how doctors think in the United States is that she recommended that treatment only be provided in the context of a clinical trial where they're collecting more data.

I think us doctors don't quite agree with that because they worry about coercing people into clinical trials, and also that it just may not be feasible that there are so many of these young people who need care that we wouldn't be able to set that clinical trial up.

JOHN YANG: Use the word coercion.

Some of the supporters of these bills also talk about young people somehow being persuaded, somehow being coerced into being transgender.

What do you say to that?

JOHN TURBAN: Yeah, I think that's more, unfortunately, a political talking point than the reality of care.

When patients come to see me, if anything, they're frustrated that I'm really slowing them down.

We're doing these comprehensive mental health evaluations, making sure they really understand what these treatments do, what they don't do.

There are difficult conversations to be had, including around things like fertility preservation.

For these kids, that's often very difficult because it can exacerbate their gender dysphoria to go through that process.

And most kids don't even access the care because there is such a strain on the system.

They need to find a therapist who can do that mental health evaluation, then they need to get into the clinic.

Then they really need to get all the education from the doctors to their family.

So it's really a slow, involved process, and I would say the opposite of anyone being rushed into it or certainly not pushed into it.

JOHN YANG: Your book illustrates a lot of your points using case histories, using some of the patients you've been treating over the years.

How long have you been doing this?

And what drew you to this field?

JOHN TURBAN: Yeah, I first came to this about a decade ago as a medical student at the time, actually, and my mentor was a journalist.

And so before I even finished medical school, I was interviewing doctors who were taking care of these kids.

And I met doctors who did essentially conversion efforts or trying to force these kids to be cisgender.

They were not having very good success.

I met doctors who were practicing this affirming model of care, which just means supporting the kids, sometimes with medical interventions, sometimes with simple things like a new name or pronouns, helping them talk to their family about it.

And I was just really struck by the experiences of these kids, that they were going through such a difficult time.

And it seemed that these affirming models of care were helping them so much.

And so eventually, that inspired me to go become a child psychiatrist.

And I've been doing this, I'd say, for about a decade.

JOHN YANG: Doctor Jack Turban, thank you very much.

JOHN TURBAN: Thank you.