When Niels was only a few months old his father Christian had been appointed as a lecturer to fill a post left vacant by the death of Peter Panum, the professor of physiology at the University of Copenhagen, and a short while later the family moved into the Panum's professorial house in Copenhagen.
Kapag Niels ay lamang ng ilang buwan old kanyang ama Christian had been hinirang bilang isang lektor upang punan ang isang post kaliwa vacant sa pamamagitan ng kamatayan ng Peter Panum, ang propesor ng pisyolohiya sa University of Copenhagen, at isang maikling habang mamaya ang pamilya inilipat sa Panum's pampropesor bahay sa Copenhagen.