All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Ash-Shirwaani from the Shaafi’i School of jurisprudence stated that there is a difference of opinion in the Shaafi'i School about the issue of stipulating that the person who recites the Athaan in cases other than calling people to the prayer must be a male and he stated that the reliable opinion is that it is a condition to be a male. However, he reported from some scholars of the Shaafi’i School that they do not condition it and that the Sunnah (in this regard) is achieved by a midwife calling the Athaan in the ear of the new-born.
Indeed, it is most likely that this last opinion is the most correct opinion because a woman does not raise her voice in this kind of Athaan. Therefore, it is permissible to ask any (Muslim) nurse to call the Athaan in the ear of the new-born. For more benefit, please refer to Fatwa 85630.
Allaah Knows best.