In my youth lessons and materials, I will be referring to God using masculine pronouns. This is not done for any definitive "God is a man!" type rationale, but rather out of respect for church tradition, and ease of speech.
Technically speaking, God exists outside the confines of gender, just as he exists outside the confines of age and time. In the Bible, God is seen to possess both traditional masculine and feminine qualities. For example, God's power is generally seen as a perfect masculine trait, while his love for his creation is typically interpreted as a perfect feminine quality.
Some find it shocking to see God referred to with feminine pronouns, but it is very interesting to note that the Bible refers to the perfect wisdom of God almost exclusively with feminine pronouns: most notably in Proverbs 1:20-22 & 9:1-6.