A P R I L F O O L S ! ! !
However, according to an article, When Houdini was President” by William Frazee in a 1953 MUM:
Some of the New York City boys told me that the research department of Paramount studios discovered that Houdini and Hardeen were step-brothers. Well, it is no surprise to any of the old timers as we all knew this, but it came as a surprise to the younger generation. As Houdini was the oldest one and both had the same mother, what was Houdini’s right name?
That said, Okito, a friend of William Frazee, wrote in the January 1954 MUM, that he had often heard rumors, yet could not possibly substantiate this fact. In the same article, Okito mentioned that when he visited his late friend Ottokar Fischer in 1926 he proved to him by authentic documents that Houdini was born in Hungary and that his name was Ehrich Weiss.