The idea goes back further than the 50s. The Soviet Union's so-called "God-builders" were interested in scientific as well as philosophical research into immortality in one form or another.
https://en.wikipedia.org/wiki/God-BuildingAlexander Bogdanov for example.
https://en.wikipedia.org/wiki/Alexander_Bogdanov"Later years and death
In 1924, Bogdanov started his blood transfusion experiments, apparently hoping to achieve eternal youth or at least partial rejuvenation. Lenin's sister Maria Ulyanova was among many who volunteered to take part in Bogdanov's experiments. After undergoing 11 blood transfusions, he remarked with satisfaction on the improvement of his eyesight, suspension of balding, and other positive symptoms. The fellow revolutionary Leonid Krasin wrote to his wife that "Bogdanov seems to have become 7, no, 10 years younger after the operation". In 1925–1926, Bogdanov founded the Institute for Haemotology and Blood Transfusions, which was later named after him. But a later transfusion cost him life, when he took the blood of a student suffering from malaria and tuberculosis. (Bogdanov died, but the student injected with his blood made a complete recovery.) Some scholars (e.g. Loren Graham) have speculated that his death may have been a suicide, because Bogdanov wrote a highly nervous political letter shortly beforehand. Others, however, attribute his death to blood type incompatibility, which was poorly understood at the time.[16]"
Conspiracy lovers these days half-jokingly say that many of the worlds elites already try using blood from children for longevity. That, or they really are vampire lords, or alien reptiloid masters, or whatever.
