DNA researchers say there is a “high likelihood” that Adolf Hitler may have suffered from a rare genetic condition that disrupted his puberty, leading him to develop a micropenis instead of normal-sized genitals.

The brutal dictator is said to have most likely suffered from Kallmann Syndrome, a condition where puberty is delayed or completely absent, according to research findings that are the focus of a new documentary, “Hitler’s DNA: Blueprint of a Dictator” airing this weekend on Channel 4 in the United Kingdom.

The scientists tested Hitler’s DNA after they obtained a blood sample from fabric torn from the sofa still stained following Hitler’s suicide in 1945.

“For 80 years, there has been lots of speculation about Hitler’s medical and psychiatric conditions,” Blink Films creative director, Dan Chambers, said in a statement announcing the company’s production. “Now, by looking into his DNA for the first time in history, we’re able to reveal a whole series of things — some that we might have expected, others that are really surprising.”

Their findings showed that there was a high chance that Hitler suffered from Kallmann Syndrome, which can cause symptoms like hearing loss, cleft palate, and underdeveloped genitals or undescended testicles.

During World War II, Allied troops sang crude songs about Hitler’s genitals, which most people assumed was just baseless propaganda. The new findings suggest that those soldiers were probably right.

“No one has ever really been able to explain why Hitler was so uncomfortable around women throughout his life, or why he probably never entered into intimate relations with women,” historian Alex Kay of the University of Potsdam, who worked on the film, said to CBS News. “But now we know that he had Kallmann Syndrome, this could be the answer we’ve been looking for.”

The research also dispels rumors that Hitler had a grandfather that was Jewish.

“Analysis of the DNA debunks this myth by showing that the Y chromosome data matches the DNA of Hitler’s male line relative. If he had Jewish ancestry (through an outside relationship), that match wouldn’t be there,” the production company said in its statement.

The researchers also claimed that his DNA showed very high polygenic risk scores, ranking him among the top one percent for predispositions to autism, schizophrenia, and bipolar disorder.

Some geneticists have thrown cold water on the findings presented in the upcoming documentary, saying that many scientists are not comfortable using this particular kind of genetic testing.

“Polygenic risk scores tell you something about population at large, not about individuals,” honorary professor David Curtis, at University College London’s Genetics Institute, told The Guardian in an article critical of the film. “If a test shows you to be in the upper percentile of polygenic risk, the actual risk of acquiring a condition may still be very low, even for conditions that are strongly influenced by genetic factors.”The British newspaper also pointed out that Blink Films and the research team had “failed to get a fresh DNA sample from any of Hitler’s surviving relatives in Austria and the U.S., who are all understandably reluctant about media exposure.”