The Russian revolution of 1917 marked the end of the Russian royal family's rule, but questions about their fate lingered. In 1991, after the fall of the Soviet Union, an amateur archaeologist revealed his discovery of a mass grave that turned out to hold the remains of the executed members of imperial Romanov family. Well, at least most of them. The remains of the Tsar, the Tsarina, and three of their daughters killed in 1918 were in the grave, but one daughter (either Anastasia or Marie) and Prince Alexei remained missing. That fueled conjecture that two children had somehow escaped the massacre, and that some Russians were actually descendants of royals on the lam.

A study published in 2009 dashed those dreams by confirming with DNA analysis that the remains found in another grave nearby belonged to the two children. But Alexei's DNA proved useful for more than identification. In another paper published in 2009, geneticists argued that the prince's DNA showed that he suffered from a rare form of hemophilia. Caused by a recessive trait on the X chromosome, the disease hinders the blood clotting necessary to stop bleeding, and appears most often in males. Alexei could have inherited the "royal disease" from his great-grandmother, England's Queen Victoria, whose own son Leopold had inherited hemophilia and died at age 31 from complications.