According to those opinions that say that Parshas Parah is a Torah obligation, do women have an obligation to attend, or would they be exempt for other reasons?
This site, citing Nitei Gavriel Purim 22:4 says:
Although women should make an effort to hear Parshat Para read in the synagogue, there is no true obligation for them to do so. Indeed, it is argued that women should be completely exempt from having to hear the Parshat Para reading because they were not involved in the sin of the Golden Calf.
Nitei Gavriel (Purim 22:4, fn6) suggests (in addition to DanF's answer from Torah Musings) that women are exempt from hearing Parshas Parah for two reasons:
- This obligation to purify oneself before Pesach is simply on the general public, not on women, and thus, individual women do not have to come and hear the Parsha
- Even if it is, it would be considered a Mitzvas Aseh Shehazman Grama, as it is limited to a particular timeframe.
He does note dissenting opinions, see there for details. I would also note that he adds earlier that most Acharonim don't Pasken that this is Deoraisa anyways.