Chaim Ozer Shulman asked:
Question:Why are women exempt from Zimun if they are obligated in benching? Mishna Brura talks about it not being Tzius or women not being experts. Is that the actual reason for their exemption?
The Kollel replies:
1) The ROSH asks your question. See Insights 45:1:b.
2) The Mishnah Berurah (OC 199:16) writes that women are not expert in the text of Birkas ha'Mazon. In SHA'AR HA'TZION, he adds that since le'Chatchilah a Zimun should be recited over a cup of wine, it is not proper to require a woman to recite a blessing and drink a cup of wine.
Nevertheless, the common and accepted practice today is that women to do not make a Zimun.