In this image made from Japan's TBS TV video on Feb. 26, 2019, North Korean leader Kim Jong-un, a habitual smoker, takes a pre-dawn smoke break at the train station in Nanning, China, hours before his arrival in Vietnam for his high-stakes summit with then-U.S. President Donald Trump over resolving the international standoff over the North's nuclear weapons and missiles. AP-Yonhap

Former President Park Geun-hye was derisively nicknamed the "toilet princess" by opposition politicians. This moniker emerged after media reports detailed the unusual measures taken by the Presidential Security Service staff during Park's state visit to the United Kingdom in November 2013.

According to a media report, the security staff set up a new toilet and replaced the showerhead at the British hotel she stayed. When Park left the hotel, they gathered her bedsheets.

The news broke in December 2016, three years after Park's UK trip, amid mounting calls for her resignation due to her controversial relationships with her confidante, Choi Soon-sil, who was later convicted for her involvement in various corruption scandals.

Some opposition lawmakers blamed Park for allegedly selfish and overly picky behavior that, they claimed, forced secret service members to go to extra lengths to make her comfortable. Park was portrayed as a spoiled, self-centered, and abusive leader. This negative characterization further aggravated an already discontented public, prompting angry citizens to gather daily at Gwanghwamun Square and demanding her resignation.

It turned out that media outlets and the Korean public overreacted to these reports.

Replacing toilets and gathering objects touched by the president are standard measures taken to protect a leader's biometric information. During their leaders' foreign trips, security staff collect their stool, urine, and saliva to prevent potential malefactors from obtaining them. They also gather drinking glasses and other objects touched by their leaders, as these items contain their DNA fingerprints.

Protecting political leaders' biometric information has become increasingly important as advances in DNA technology reportedly enable people to glean extensive health information from their genetic data.

Political scientist Hahm Sung-deuk said a president's health should remain secret, because it is directly related to national security. "Presidents are in a position to make critical decisions that can have far-reaching impacts on their countries," he told The Korea Times. "If they are not in good health, this would inevitably affect their ability to make proper decisions."

Then-President Park Geun-hye and Britain's Queen Elizabeth make a toast at a state banquet at Buckingham Palace in London, Nov. 5, 2013. Reuters-Yonhap

It is an open secret that intelligence agencies have actively sought foreign leaders' biometric information. In a classified diplomatic cable, the U.S. Department of State which was then under the leadership of Hillary Clinton, directed U.S. embassies overseas to collect detailed biometric information of foreign leaders and U.N. officials. Regarding North Korea, for example, the department instructed its officials to gather "biographic and biometric information on senior North Korean diplomats."

Intelligence agencies strive to obtain the DNA data of foreign leaders, recognizing it as a valuable source of information about their health. Successfully acquiring this data could thus become a critical intelligence asset. It can help people understand events in reclusive countries, such as North Korea, where internal affairs are notoriously opaque.

Kim Jong-un's father, Kim Jong-il, and grandfather, Kim Il-sung, who ruled North Korea before him, both died of cardiac problems in 2011 and 1994, respectively. Their sudden deaths escalated tensions, as the resulting leadership vacuum threatened to destabilize the country and potentially disrupt regional security.

If other countries had known about their health conditions in advance and predicted the likelihood of sudden deaths, they would have been better equipped to handle the potential instability.

Experts are divided on the use of genetic information as a tool for diagnosing people's health conditions.

Lee Dong-sung, a professor of life science at the University of Seoul, said biometric information has enormous potential to reveal details about an individual's health. "DNA samples extracted from stool, urine and saliva have much information about a person's health condition," he said. "If people are severely ill, DNA tests can tell what diseases they have."

But other experts are cautious about genetic information.

Ryu Young-joon, a pathologist and professor at Kangwon National University College of Medicine, expressed skepticism regarding DNA samples as an indicator capable of showing people's health status in great detail. "With DNA fingerprints, you only know whether you have certain diseases or not. They can also tell whether you are seriously ill or not. DNA data would let you know basic information about your health, such as your family's medical history and underlying medical conditions," he said.

Ryu said there is a more important aspect of DNA tests -- identification. If scientifically used, he said DNA data can aid in identifying individuals who are being sought after. He suggested that intelligence agents who are interested in knowing the whereabouts of North Korean leader Kim Jong-un, would be tempted to seek and use genetic information.

"Let's say that Kim is known to be heading back home on his train after wrapping up his trip to a foreign country. The intelligence agent will want to confirm whether this is true or not, so he searches for a garbage can at the venue Kim was last spotted before his departure. And he finds a used tissue confirmed to have Kim's DNA samples. If his agency already has Kim's DNA data, the agent would request his agency to compare it with the DNA samples extracted from the tissue. If they match, the agent can confirm Kim is in the train heading to North Korea," Ryu said.

Two men bring a toilet to a hotel in Hanoi, Vietnam on Nov. 24, 2019, three days before North Korean leader Kim Jong-un held a summit with then-U.S. President Donald Trump. Yonhap

Predict the unpredictable

His remark also suggested that genetic information can be used to determine whether a person is a body double, a tactic often employed by autocratic leaders for various reasons.

North Korea is keen to protect the biometric information of its leader and other royal family members.

On February 24, 2019, two unidentified workers were seen transporting a toilet to the hotel where North Korean leader Kim Jong-un stayed during his visit to Vietnam for a summit with then-U.S. President Donald Trump, just three days before the event.

One of the South Korean journalists who was there to cover the summit later mentioned that she understood the additional toilet was intended for Kim Jong-un's use. However, she could not comprehend why the North Korean leader would require an extra toilet, given that the hotel already had one. She said it still remained a mystery to her.

Kang Cheol-hwan, president of the Seoul-based NGO North Korea Strategy Center, mentioned that the practice of collecting stool, urine, and other items with DNA fingerprints of heads of state has been ongoing in North Korea. However, he admitted he did not know when this practice started.

"Anything about the supreme leader's health is sensitive information because in North Korea, his health condition is directly related to the survival of the country. Fully aware of this sensitive nature, North Korean officials make every effort to keep that information safe, so that it cannot be handed over to foreign intelligence agencies," he said.

A defector-turned-NGO leader, Kang said the North Korean leader's sister, Kim Yo-jong, is another royal family member whose biometric information is also strictly protected.

According to Kang, her bodyguards collected her stool and urine and took them back to the North when she visited South Korea during the PyeongChang Winter Olympics.

During her three-day visit to South Korea in February, 2018, Kim Yo-jong stayed at the Walkerhill Hotel in Seoul.

"She didn't use the bathroom of the hotel, and instead she used the toilet her bodyguards brought from Pyongyang," Kang said, adding that he found out that information from an intelligence agency.

In 2018, Kim Jong-un was filmed by a Japanese broadcast taking a cigarette break at Nanning rail station in China, just three hours before he arrived in Vietnam for a summit with Trump. While he was smoking, his sister Yo-jong stood nearby holding a crystal ashtray for her brother's leftover cigarette butts.

Experts interpreted the scene as evidence of efforts to protect the biometric information of the North Korean leader. The cigarette butts contain Kim's saliva, so if collected, one can extract his DNA samples from them.

It remains unknown since when the biometric information of world leaders began to be used to assess their health conditions.

Park Seung-gyu, a professor at Daejeon University, said the practice has persisted for centuries.

"During the Joseon Dynasty, there was a mobile toilet called "Maewha-teul" or Prune Fixture. It was the king's toilet. Royal doctors would check a king's stool to find out if he has any health problems," he said.

Speaking on condition of anonymity, a doctor remarked that genetic fingerprints are not perfect and cannot precisely determine an individual's health. When assessing the North Korean leader's health, he emphasized that a holistic approach would be more accurate than relying solely on DNA data.

"When I see my patients, I try to look into various factors that can affect their health conditions. On top of their current health conditions, I also look at factors like obesity, drastic weight loss, family health history, and underlying conditions before diagnosing their diseases and what they have to do to recover," the doctor said.

He added that DNA samples and fingerprints are among the factors that can provide insights into people's health conditions.

Then President Moon Jae-in speaks to North Korea's special envoy Kim Yo-jong during her visit to Korea for the PyeongChang Winter Olympic opening ceremony in 2018. Yonhap