Before we can start with a DNA analysis we are obliged by law to ensure that each participant has given their written consent to the test. For persons under age consent must be given by all persons having custody.
In Germany, all DNA testing is regulated according to the Gene Diagnostic Act which came into effect in February 2010.
Since then it is mandatory that DNA tests must only be performed with the written and formal consent of each participant. No more clandestine tests may be done. Not only the testing laboratory may be liable for prosecution but also the customer who ordered the DNA test.
Accordingly, we are obliged to ensure that all participants have been sufficiently informed and have given their written and formal consent. If the mother should refuse her consent your only chance is to obtain a court order that enforces her consent.