Let's assume he's 16.
In 1995, the year of his birth, we produced the first atom of antihydrogen.
Last year we produced cold antihydrogen and kept it around for a sixth of a second. Earlier this year we replicated that feat and kept it stable for an entire 15 minutes of study. We also produced some Antihelium-4.
Also in 1995 a speech at a meeting of string theorists united the major string theories of the time into M-Theory, or Brane Theory.
1995 also was the year of the discovery of the Top Quark, which was found to be a lot more massive than previously predicted.
In 2000 we discovered the Tau Neutrino.
In 2002 and 2004 strong evidence was produced for Sagittarius A being a supermassive black hole at the center of our galaxy.
Results from the LHC this year have ruled out the existence of the Higgs Boson with roughly 95% certainty. The lack of any observed SUSY particles being produced at the LHC also is an ominous portent for the future of supersymmetry theory.
I'm sleepy and lazy and that's just some quick googling. There's more. And even more massive breakthroughs if you count the 80's and 70's which, while not in Gedeons' literal lifetime. I would say are part of "our" lifetime. At least the 80's.