This is a simple and loaded question all at the same time. The Jewish name for mother is "em" or "emah." Simple right? However, the next question that I usually get asked after this is some variation of this, "Can God be both our father and mother?" This is the loaded question. Because no matter how I answer, someone will think that I am supporting something that I am not. Can't win. But I will try my best to answer it within the limits of wisdom that God has given me and the keyboard that I am typing on at this moment.
First, and foremost, I believe the best and only thing we can do is to refer to God in the masculine sense. For while there are passages in which a more maternal side of God appears (Hosea 13:8 is one metaphorical example), the overwhelming Biblical evidence is that while God is not restricted or bound to our understanding of gender, our understanding of God is best seen through the use of male-oriented language. To refer to God using female pronouns is at best disrespectful and at worst, something which approaches the blasphemous. Those who try to be so gender inclusive in regards to God lose the essence of what Scripture wants to teach us. God is our Father who sent His Son to die for our sins. And in fact, Jesus himself teaches us how to address God through the Lord's Prayer (Matt. 6:9-13), "Our Father," and through the agony of the cross, "Father, into thy hands I commit my spirit" (Luke 23:46).