In 2364, he was stationed at Starbase 74. While there, Crusher hoped to consult him regarding her proposals for combining cybernetics with medical regeneration. (TNG: "11001001")
A small scene in the script, which was cut from the episode, had Crusher speaking with Epstein in a starbase conference room. He was established as a young man of twenty-six years old. In his fifth paper on molecular biology, he defined the problem as conductivity.