Oh, brother.

"Men but not women get to preside at Mass. Men but never women wear the cassock of a cardinal, the vestments of a pope. Male clergy are typically called 'father,' which connotes authority. Women in religious orders are usually called 'sister,' which doesn�t."

Says Frank Bruni in the middle of a rant titled "Catholicism Undervalues Women."

Whatever else he may want to say about Catholics and women, there's no lack of parallelism in that father/sister terminology. Men in religious orders are called "brother," and female leaders of orders are called "mother."