If you are claiming German citizenship by descent because your ancestors lost or were denied their citizenship during the Nazi era, it does not matter which of your ancestors was affected or what their gender was. It could have been your mother, grandmother, father, or grandfather — the requirements are the same.
However, if you are claiming citizenship by descent due to gender discrimination that occurred after the Nazi era, then it does make a difference whether your lineage is maternal or paternal. According to § 5 Law on Citizenship, you are generally entitled to naturalization by declaration if your mother or grandmother was a German citizen and their children did not automatically acquire German citizenship due to the discriminatory laws in force at the time.
There is, however, one case under § 5 in which the parental lineage must be paternal: you may declare your wish to become a German citizen if your father or grandfather was German but not married to your mother or grandmother. In such cases, their children also did not acquire German citizenship by birth.
Further information on the requirements under § 5 Law on Citizenship can be found here.