Lumen, I also have no direct knowledge about Muslim sensibilities re Allah and gender, and the use of pronouns to refer to him.

However, the would think it is a reasonable presumption that the issue in Islam is similar to the situation among Christians. That is:
* traditionally God is regarded as male and referred to with male pronouns
* but it is also true, I assert, that if at anytime in the last 2000 years one had asked a professional theologian whether God is masculine, the reply would have been that obviously God does not have gender; and our traditional usage is simply a convention, but a convention supported by such central Christian artifacts as the Our Father and the Creed.
* in recent times, scripture scholars have brought forward multiple female metaphors for God in the OT, and especially female references for the Holy Spirit as Wisdom. 
* therefore, it has become a common place among many Christians to stress the fact that God has no gender, by calling God Mother and her