This interesting YouTube video asks the question: "Why Did the World’s Best Chess Player Go Insane?" without really answering its own question. It also makes the suggestion, again unsupported by any references, that Fischer's real father was Hungarian mathematician, Paul Nemenyi.

So, who was Fischer's real father? Is there any supporting evidence for the case for it being Paul Nemenyi?

  • He was a father of a world championship winner.. also, he was a man.
    – ShadYantra
    Commented Apr 30, 2023 at 19:14
  • the hbo documentary bobby fischer against the world also mentions paul nemenyi iirc
    – cmgchess
    Commented Apr 30, 2023 at 19:48

2 Answers 2


The answer is that we don't know for certain. Short of exhuming the bodies of Nemenyi and Fischer*, taking DNA samples from each, and testing those samples, it seems likely we will never know for certain who Bobby Fischer's biological father was. Even then, we may not have 100% certainty.**

Regina Fischer's (Bobby's mother) marriage to Hans-Gerhardt Fischer didn't last all that long. Personal issues may have played a part, but Regina's Jewish heritage led her to flee Moscow (where she and Hans-Gerhardt were living) for Paris. Nonetheless, Joan Fischer (Bobby's sister or, apparently more correctly, half sister) is believed to be a result of the marriage. Joan went with Regina to Paris (and later the U.S.) However, it is believed that Regina and Hans-Gerhardt had no in person contact with one another around the timeframe in which Bobby was conceived.

There is circumstantial evidence supporting Paul Nemenyi as Bobby's biological father. It is known that Regina and Paul had an affair in the timeframe around which Bobby would have been conceived. Also, Nemenyi paid money to Regina until his (Nemenyi's) death, which has been said to be support for Bobby. Nemenyi was also observed to have taken an interest in Bobby. Unfortunately, Nemenyi died in 1952, shortly before Bobby turned 9.

While I'd previously read or heard most of the things about Fischer, et al. that I stated above, I relied on the Wikipedia article about him to refresh my memory as I was writing this answer. The sources cited there may provide more information if you want it.

* A DNA sample for Fischer may already exist, as his body was exhumed to help settle his estate. A woman claimed that her daughter was Fischer's child and thus entitled to inherit some of his money. (The resulting DNA test showed that to be false.)

** I'm not a biologist, let alone DNA specialist, but I do know that DNA can deteriorate over time, so at some point the testing would become inconclusive or even impossible.

  • But why people are interested in digging the grave of father and son...
    – ShadYantra
    Commented May 1, 2023 at 9:32
  • 4
    @ShadYantra: Sorry if I was unclear. I wasn't saying people are interested in digging up their graves, nor was I advocating for it, I was just trying to say that doing so seems to be the only way that could prove or disprove the paternity issue in question here.
    – GreenMatt
    Commented May 1, 2023 at 12:40
  • But people are assuming things. I am sorry to great champion. If there are doubts then put it like unknown or no information.
    – ShadYantra
    Commented May 1, 2023 at 18:24
  • @ShadYantra: The answer starts by stating that we don't know who Fischer's father was for sure. Thus I don't understand what your objection is. Also, I don't know what you think people are assuming.
    – GreenMatt
    Commented May 1, 2023 at 20:53
  • Though i had objection over the question but not on answers.. People are at freewill
    – ShadYantra
    Commented May 2, 2023 at 4:14

I found this interesting Chess.com article which goes into the question in more depth. It gives short biographies of Paul Nemenyi, Regina Wender Fischer and Hans-Gerhardt Fischer along with some details for Joan Fischer, Bobby's older sister, and Peter Nemenyi, his likely half-brother.

Here is how the article describes how Nemenyi and Regina Fischer met:

In 1942, Dr. Paul Nemenyi, age 47, met Regina Wender Fischer (1913-1997), age 29, in Denver, according to FBI files. Regina was taking classes at the University of Denver while working at a company that made chicken incubators. She was a mother of a 5-year-old girl, Joan Fischer. Her husband, Hans-Gerhardt Fischer, was in Santiago, Chile. He was barred by immigration authorities from entering the United States.
In the summer of 1942, Dr. Paul Nemenyi and Regina Fischer were romantically linked, probably had an affair, and he may have fathered Bobby Fischer.

and Regina and Hans-Gerhardt Fischer's early life together:

Hans and Regina moved to Moscow in 1933 and were married in Moscow on November 4, 1933. She was 20, he was 25. He was a biophysicist working at the Moscow Brain Institute. She was studying medicine at the First Moscow Medical Institute and he was studying biophysics.

Their first born child, Joan Fischer, was born in Moscow in 1937. She died in 1998.

On July 29, 1938, Regina went to renew her passport at the American embassy. She told a staff member that she had separated from her husband. At about this time, Hans-Gerhardt had left or was sent to operated on the Republican side in the Spanish civil war to fight the Fascists.

In late 1938, Regina and Joan departed for France and met up with Hans-Gerhardt in Paris. It's possible they also went to Austria.

On January 23, 1939, Regina Fischer left France and headed to the United States with her daughter, Joan. ... She caught one of the last ships leaving France for America. It is not clear if Hans-Gerhardt was on this ship (he did not have a U.S. passport, but had a Spanish passport). The FBI does say that Hans-Gerhardt Fischer never entered the United States from any ship (was he a suspected Soviet spy?).

The FBI file says that Hans Gerhardt Fischer lived for a time in Port San Antonio and Santiago, Chile where he sold and installed fluorescent lights and worked as a photographer. He landed in Chile on January 4, 1940.

It goes on:

Regina later divorced Hans-Gerhardt on September 14, 1945 on the grounds of willful neglect to provide for her and her two children. At the time of divorce, Regina was living in Moscow, Idaho. He never lived with her in the United States. He remained a lifelong German citizen.

So, unless she visited her husband in Chile in summer 1942 it is impossible for him to be the father.


Dr. Nemenyi took a deep interest in Bobby Fischer and even paid child support to Regina. At one time, in 1947, when Bobby was 3, he complained to a social worker about the way Regina was raising Bobby. He told the caseworker that Regina was mentally upset and Bobby was an upset child.

In 1949, Dr. Paul Nemenyi went to a social worker again, complaining that his son was not being brought up in desirable circumstances, due to the instability of Regina.

So, Nemenyi acts like Bobby's father. Then:

Dr. Paul Nemenyi died of a heart attack on March 1, 1952, at the age of 56. He had just stopped at a dance at the International Student House in Washington, DC. There, he dropped dead of a heart attack. He was living in Washington, DC, and working at the U.S. Naval Research Lab. He was survived by his son, Peter , a civil-rights activist. Peter wrote that his father, Paul, was the father of Bobby Fischer.

At the time of his death, Paul was paying for 8-year-old Bobby’s education and sending $20 a week to Regina.

Then the question of what to tell the young Bobby Fischer?

Regina did not want to tell Bobby of Paul Nemenyi’s death and was hoping that Peter Nemenyi would do it. He was not comfortable with that, so he consulted a family doctor for advice. He wrote to his family doctor, “I take it you know that Paul was Bobby Fischer’s father. The matter is further complicated by the false pretenses about Bobby’s identity and the parents’ difference of opinion over the question.” Peter felt he was not qualified to tell Bobby about Paul’s death since Peter had met Bobby only a few times.

The full article is a fascinating read and lays out strong circumstantial evidence that Nemenyi was Bobby's biological father.

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