A Polish nationalist member of the European Parliament may be punished after he said women "must earn less than men because they are weaker, smaller and less intelligent".
The parliament's president is investigating whether Janusz Korwin-Mikke broke the body's rules with his remarks to fellow MEPs.
The rules ban defamatory, racist or xenophobic language or behaviour.
Socialist MEP Iratxe Garcia-Perez was seen criticising Mr Korwin-Mikke.
Parliament President Antonio Tajani was urged by the Socialists and Democrats (S&D) group to sanction the Polish MEP for his "shameful" comments.
Penalties for such behaviour range from a reprimand to a fine and temporary suspension, the parliament press office told the BBC.
Rule 11 of the Rules of Procedure says MEPs' conduct "shall be characterised by mutual respect" and they "shall not resort to defamatory, racist or xenophobic language or behaviour in parliamentary debates".
Mr Korwin-Mikke - an independent MEP with his own political party - has been censured before by the parliament.
Last year he lost 10 days of attendance allowances (€3,060; £2,633) and was suspended for five days for comparing Europe's influx of migrants to "excrement".
In October 2015 he was suspended for 10 days for making a Nazi salute in the chamber. Italian MEP Gianluca Buonanno was punished for the same offence.