These major religions have used fear and dominance for centuries to force people into believing their religions. Just look at the religious wars that continue to happen. The people who questioned the current leader were presecuted and their knowledge and opinion erased.
Men (male beings) wrote much of what is now used as our instructional books for religion ( The Bible, the Koran, the Book of Mormon).They feared and didn't understand the power of women so they excluded them from the writings. There is very little written about the wives, daughters, and female soldiers who helped to build these religions.
Some ancient societies gave women the recognition they deserved and worshipped Goddesses and Gods. The fact that women bear children , and men couldn't handle the phsyical pain of child bearing, is enough for male egos to be out of whack! God created male and female which seems to say to me that there was a female image with God for him to copy.He again used male and female throughout nature. If there was no need to have females then God would have created one sex! But he created them to compliment each other and fufill his plan.
Until recently(historically and after the ancient times) women could only hold subserviant positions in the "big" religions and that again speaks to the male role of domination. There is so much to read about that offers information about the role of women and why they were left out of relgion. Past religions that have been presecuted into non exsistence have exhalted women. (the Rosacurcians, the Gospel of Mary, The Gnostic religion to name a few)
So basically the reason men have made God only male is out of fear of their own limited understanding of creation and not being willing to share the "spotlight" so to speak.