Green party lawmaker Britta Hasselmann had noted during a speech on gender equality in politics that women make up only a small share of Alternative for Germany's parliamentarians, to which an unidentified member of the party reportedly replied: "Natural selection."
Deputy speaker Claudia Roth called on the party, known as AfD, to respect parliamentary protocol.
Separately, German public broadcaster ARD reported Thursday that the far-right party submitted an incorrect list of donors who it claimed had given money to co-leader Alice Weidel ahead of 2017 national elections.
ARD reported that several of the people named on the list Alternative for Germany submitted to parliament denied giving money to Weidel.
AfD did not immediately respond to emailed requests for comment on both issues.