But God’s Spirit (ruah) has a feminine gender (grammatically) in Hebrew.
Pope John Paul I refered to God as Mother:
"And Premier Begin recalls that the Jewish people once passed difficult moments and addressed the Lord complaining and saying: “You have forsaken us, you have forgotten us!” “No!” —He replied through Isaiah the Prophet—“Can a mother forget her own child? But even if it should happen, God will never forget his people”.
“Also we who are here have the same sentiments; we are the objects of undying love on the part of God. We know: he has always his eyes open on us, even when it seems to be dark. He is our father:
even more he is our mother. He does not want to hurt us, He wants only to do good to us, to all of us. If children are ill, they have additional claim to be loved by their mother. And we too, if by chance we are sick with badness, on the wrong track, have yet another claim to be loved by the Lord.”
ewtn.com/library/PAPALDOC/JP1PRAYR.HTM
Julian of Norwich also referred to God as Mother (anyone know if she is a Blessed? Scott Hahn refers to her that way “Blessed Julian…”):
vatican.va/spirit/documents/spirit_20010807_giuliana-norwich_en.html
Apparently Catherine of Siena spoke of the Holy Spirit as mother:
“The Holy Spirit becomes [for people who abandon themselves to Providence] a mother who feeds them from the breast of divine charity.”
salvationhistory.com/library/tradition/theology/appendix%20and%20notes.pdf
In the above link, you can also read Scott Hahn’s thoughts.
As for me, I think if we have a God as our Heavenly Father it would be strange to think we are without a divine Heavenly Mother and also strange to think that the Heavenly Father would be alone without a feminine companion. Since Jesus refers to his God as Father, he must be masculine
in some sense of the word or after some manner of speaking – otherwise Jesus’ use of the word “Father” would be
arbitrary. But maybe some persons – namely divine persons – are beyond romantic relationships and romance and spiritual sexuality has not a cosmic significance but is a mere detail of some finite creatures.
Some philosophers use “she” in reference to God. When I was a tradition-minded Catholic it bothered me a little bit, but now I’m accepting of it.