What is the ruling on Dr. Amina Wadud leading worshippers (men and women) in prayer in America, with a girl calling the adhan, and her not wearing a hijab?

The majority of scholars hold that it is not permissible for a woman to perform the adhan (call to prayer) for men, just as it is forbidden for her to uncover her head in front of non-mahram men. Her prayer becomes invalid if her head is uncovered, unless she is a slave woman. The Hanafis considered maleness among the sunnahs of the adhan and disliked a woman's adhan; Abu Hanifa recommended repeating it. However, some Shafi'is permitted her adhan for a congregation of women, provided she does not raise her voice.