IT was a rare public sighting of Russia’s premier political couple, but in the end it served only to fuel the already rampant questions about whether they are much of a couple at all anymore.

Lyudmila A. Putin entered a polling station on Election Day last month half a step behind her husband, Vladimir V
Putin, the once and future president. At one point, she touched his arm, but he never reached out in return.

When an election worker pointed to candidate information on a wall, Putin said he did not need it, but gesturing at his wife of 29 years, he added, “She’s not up to speed.” Lyudmila Putin chuckled. Then her husband left her behind, walking away to insert his ballot in the box and to talk with reporters while she continued to fill out paperwork.

Though they ultimately left with her holding his arm, some of the reaction the next day was biting. One photograph, which circulated on the Internet, showed Putin seeming to shake his wife’s hand at the polling station. The caption said, “Until we meet in six years” – when he is next up for re-election.

The Putins are seen so rarely together that it is unclear if she will attend his inauguration on Monday or if she will perform any duties as first lady during Putin’s new term.

The Election Day appearance was a reminder of the nearly impenetrable secrecy that has enveloped them and their two daughters since Putin, a former KGB agent, rose to power 12 years ago. The longer he rules Russia, the more discussion of his family life seems taboo.

The Russian leader and his wife are widely believed to live apart, but it is unclear where she spends most of her time. Their daughters attended college under assumed names, and many of their classmates did not know their true identities. Even now, it is not known if they live in Russia or abroad, and what, if anything, they do professionally.

Russian journalists say it is easier to report on national security issues than on the Putin family, and there often seems to be an unspoken threat that there will be serious repercussions if reporters dig too deeply.

In 2008, when a reporter for Moskovsky Korrespondent wrote about rumors that Putin planned to divorce his wife and marry Alina Kabaeva, an Olympic gold medalist in rhythmic gymnastics who is less than half his age, Putin forcefully denounced the report, and the newspaper promptly shut down.

Shortly after that, Putin traded the presidency for the prime minister’s office, and Lyudmila Putin virtually disappeared from view. In 2011, she attended a concert in honor of what would have been Boris N. Yeltsin’s 80th birthday and Easter services at the Cathedral of Christ the Savior in Moscow. This year, she skipped the Easter celebration.

Even more extraordinary is the virtual invisibility of their daughters: Maria, 27, and Yekaterina, 25. They are members of the Facebook generation who cannot be found on Facebook or any other social media site and who have defied the Western trend of political offspring becoming public figures as they grow up.

While there are a handful of photographs of the girls from their early childhood, they have been seen so rarely in recent years that most Russians would not recognize them.

When Putin recently agreed to give extraordinary access to a German documentarian, there was one condition: His private life was off limits, said the filmmaker, Hubert Seipel.

The documentary, “Ich, Putin,” released this year, portrays Putin as largely alone, spending more time with his bodyguards and his dog than with his family. In an interview, Seipel seemed vexed when asked if, in the hundreds of hours he spent with Putin over more than a year, he had ever seen the family, or if Putin was truly as isolated as the film suggests.

Seipel said he attributed Putin’s sensitivity to a “Soviet style” that differed sharply from the Western practice of putting political families on public display.

But it is hard to generalize. Stalin’s daughter, Svetlana, enjoyed a highly public profile in childhood, and later caused a sensation by defecting to the United States. Yeltsin’s wife, Naina, was rarely seen in public. But his younger daughter, Tatyana Dyachenko, served as a trusted adviser in his final years.

Putin has aggressively asserted a right to privacy, and his office declined to comment for this article.

He has often said that he wanted his daughters to live a “normal life.” Oleg Roldugin, an investigative reporter who wrote a lengthy article about Putin’s family for the newspaper Sobesednik, said that Putin seemed to have succeeded.

The sort of Internet search that yields countless images of Sasha and Malia Obama offers virtually nothing about the Putin daughters.

One rare, genuine photograph shows them as teenagers standing with their father on a boat with their backs to the camera. There is also a photograph of a grown-up Maria Putin, walking with her parents, running a hand through her blond hair.

Only thin sketches are known about their lives. Both daughters attended German-language schools and St.

Petersburg State University, where Maria studied biology and Yekaterina majored in Asian Studies. Both have been linked romantically to foreigners.

A South Korean man, Yoon Joonwon, whose father worked at the Korean Embassy in Moscow, confirmed recently that he had dated Yekaterina but denied they were planning to marry. Dutch and Russian news reports have connected Maria to Jorrit Faassen, a Dutchman who has held high-level positions at subsidiaries of the Russian state gas company, Gazprom.