I think that God needed to be described as a man because of the patriarchal views that majority of all civilizations had and still have at the time, and that is why Jesus was sent to Earth in the form of a man. If God or Jesus were women, I don't think that Christianity would have spread or Jesus would have been taken seriously at all. God knew this and decided that what was best for "his" people was to be portrayed as a man through Jesus. I personally do believe that God is gender-less (and not human for that matter) but we cannot imagine what God looks like so people personify God in a way that they can understand, which for many people (especially when the Bible was written) is as a man. However, I do not think that the spread of Christianity or the idea of God being a man necessarily created or enforces patriarchy because that mindset already existed before Jesus. Also there are many civilizations where Gods of both genders are believed in, but a patriarchal society is still present.