Doktor werden ist nicht schwer ... 
Completed doctoral theses, supervision Alfred H. Gitter

In Germany, physicians do NOT get a "MD" automatically, i.e. without a doctoral thesis.
Instead, they must prepare a full doctoral thesis to get the title "Dr. med.".
Biologists and biochemists get a "Dr. rer. nat.".  These titles are scientifically equivalent to a PhD.

Co-supervision A.H. Gitter