There's this famous gnostic text called The Gospel of Thomas that tells a story where Jesus tells Peter that he will androgynize those in his kingdom. That's the version of Christian mysticism that Julian arrives at. She likens the goal of understanding the difficult paradoxical nature of God's love with the problem of evil on the earth to the also difficult paradox of gender and the creation of life in a mother's womb. She arrives at a perfect androgyny, saying that Jesus Christ is her own mother.
Joseph Campbell noticed the androgyny of mystic religious traditions all over the world, so Julian can be thought of as a kind of mystic. That simply means that she studies all the philosophical implications of the religious mysteries in Christianity. Although the church has fundamentally opposed many of the ideas she is hinting at, the Bible is clearly on her side in her rigorous pursuit of higher truth than societal truth. One might remember verses about the "narrow path" to bliss, or the strange proclamation from Paul that, "In Christ there is no male or female." This combination of seemingly opposing forces is the thrust of mysticism and it's plainly evident here.
That's because the problem of evil requires a paradoxical response. It is a paradoxical question, and it is synchronous with human emotions, because like Julian herself notices, she has emotional stake in her understanding of God. By eliminating her sense of shame and inhibition, she attains states of blissful consciousness where she feels enlightened by the very love of an unfathomable creator, a creator who she calls Jesus the mother. Jesus as a mother is an idea of much philosophical merit.
