I don't personally think one can take a vow of 'Obedience' and then proceed to redefine what one is prepared to obey. Social mores and fashions come and go, and the Catholic Church has usually upheld the traditional, long-held tenets as much as possible. I'm not by any means stating my own personal views on,say, abortion or same-sex marriages. (Actually I'm anti-abortion and pro-gay marriage, also pro-contraception.) I totally agree that reforms are due. But the position of a nun (or male religious) is quite clearly defined, and not in any way the same as that of a lay person.