Cory Russo, the chief death investigator in Utah, is used to asking strangers questions at the most excruciating moments of their lives. When she shows up at the scene of a suicide, a homicide or another type of unexpected death, her job is to interview the grievers about how the deceased had lived.

How old were they? What was their race? Did they have a job? Had they ever been hospitalized for psychiatric issues? How had they been feeling that morning?

Over the past couple of years, she has added new questions to the list: What was their sexual orientation? What was their gender identity?

Ms. Russo, who works in the Office of the Medical Examiner in Salt Lake City, is one of the relative few death investigators across the country who are routinely collecting such data, even though sexuality or gender identity can be relevant to the circumstances surrounding a person’s death.

She recalled the recent suicide of a young man who died in the house of older adults. During her interviews, Ms. Russo learned that the man had been living with them for a year, ever since his family had kicked him out of their house because he was gay. He had struggled with emotional upheaval and addiction.

“It was heartbreaking to hear,” said Ms. Russo, a lesbian who has lost loved ones to suicide. “In that case, it was very relevant to understand that piece.”

Studies of L.G.B.T.Q. people show they have high rates of suicidal thoughts and suicide attempts, factors that greatly increase the risk of suicide.

But because most death investigators do not collect data on sexuality or gender identity, no one knows how many gay and transgender people die by suicide each year in the United States. The information vacuum makes it difficult to tailor suicide prevention efforts to meet the needs of the people most at risk, and to measure how well the programs work, researchers said.

The absence of data is especially unfortunate now, they said, when assumptions about suicide rates among L.G.B.T.Q. groups are frequently thrust into high-stakes political debates. Some L.G.B.T.Q. advocates have warned that bans on gender-affirming care for transgender minors will lead to more suicides, for example, while some Republican lawmakers have claimed that deaths by suicide are rare.

Utah, which like many mountain states has a high rate of suicide mortality, has been at the forefront of efforts to collect such data since 2017, when its State Legislature passed a law mandating detailed investigations of suicides.

The lawmakers were “frustrated with being asked to respond to the suicide crisis in our state with a blindfold on,” said Michael Staley, a sociologist who was hired to lead the data-collection effort in the Utah medical examiner’s office. “It’s a five-alarm fire.”

In the months after investigators like Ms. Russo show up at the scene of a death, Dr. Staley’s team of six people conducts “psychological autopsies,” contacting family members of everyone in the state who dies by suicide or drug overdose for detailed information about the lives of the deceased.

Such data — which includes information on sexual relationships and gender, as well as housing, mental health, drug problems and social media use — can be used to help understand the complex array of factors that contribute to people’s decisions to end their lives, Dr. Staley said. He plans to release a report later this year describing interviews with the families of those who died by suicide in Utah over the last five years.

For children and adolescents who die by suicide, the team interviews not just parents and guardians, but also several close friends. In some cases, Dr. Staley recalled, friends knew about the deceased’s struggles with sexuality, gender or drug use that the parents did not.

These conversations can be exceedingly difficult. John Blosnich, head of a research initiative called the L.G.B.T. Mortality Project at the University of Southern California, has done ride-alongs to observe and train death investigators on the importance of collecting data on gender and sexuality. His training also helps investigators navigate distress or stigma about the questions from the deceased’s friends and relatives.

“They’re talking with families who are in shock, who are infuriated, who at times are catatonic because of their loss,” Dr. Blosnich said.

So far, Dr. Blosnich has trained investigators in Utah, Nevada, Colorado, New York and California, where a 2021 state law started a pilot program to collect data on sexual orientation and gender identity. In a recent study of 114 investigators in three states, Dr. Blosnich reported that only about 41 percent had directly asked about a deceased person’s sexual orientation, and just 25 percent had asked about gender identity, before going through the training.

Medical examiners send reports of homicides and suicides to the Centers for Disease Control and Prevention, which maintains a database of violent deaths with extensive demographic, medical and social information, including toxicology tests, mental health diagnoses and even stories of financial and family hardships. But a study of more than 10,000 suicides among young adults reported to the C.D.C. database found that only 20 percent included information on the deceased’s sexuality or gender identity.

Another agency in the health department, the Office of the National Coordinator for Health Information Technology, is trying to set new standards that would require any hospital that receives federal money to ask its patients about their sexuality and gender identity.

Death investigators are “limited by the fact that they can’t ask the person the question,” said Dr. John Auerbach, who worked on standardizing questions about sexuality and gender at the C.D.C. from 2021 to 2022. If doctors were routinely talking to their patients about sexuality and gender identity, that information could help answer other public health questions as well, such as those regarding the relative risk of cancer or diabetes in the L.G.B.T.Q. community, Dr. Auerbach said.

But that approach has its limits. Patients may not feel comfortable disclosing that information to their doctors. And those who don’t interact with the health care system may be at especially high risk of suicide.

L.G.B.T.Q. advocates said that obtaining that data had become more urgent in the past couple of years, as states across the country have imposed restrictions on many aspects of life for gay and transgender people.

“Lacking in data, it is all too easy to dismiss us,” said Casey Pick, director of law and policy at the Trevor Project, a nonprofit organization focused on suicide prevention among L.G.B.T.Q. young people that has lobbied at the state and federal levels to begin collecting that data.

“I have heard it too many times: Lawmakers and public witnesses in hearings suggest that the L.G.B.T.Q. community is crying wolf on suicide because we don’t have this data to point to,” Ms. Pick said.

It’s also important to acknowledge the unknowns, Dr. Staley said. Although studies have reported a high rate of suicidal thoughts and suicide attempts among lesbian, gay and transgender people, that doesn’t necessarily mean a high rate of suicides. He noted that although women have a higher rate of suicide attempts than men do, men have a much higher rate of dying by suicide, partly because they have more access to guns.

And Dr. Staley, who is gay, cautioned against political narratives that “normalize suicide as part of the queer experience.”

“I would argue that if anything, this life experience sets us up to be resilient,” he said. “Our fate is not sealed. Our story is not written.”

If you are having thoughts of suicide, call or text 988 to reach the 988 Suicide and Crisis Lifeline or go to SpeakingOfSuicide.com/resources for a list of additional resources.