In the Book of Wisdom, Wisdom is a "she" because the book is written in Greek, and the Greek word for "wisdom" is sophia, which is a feminine noun. But, we should not take this to mean that God is actually a female.
The author of the book (traditionally considered to be King Solomon) is simply using a literary device called "personification" to emphasize one of God's divine attributes: wisdom. This is fitting, considering that God IS his various attributes. God is not simply loving, He IS love. God is not simply wise, He IS wisdom. So, to strive for Godly wisdom -- to be wise as God is wise -- is to strive for God Himself. Where ever wisdom prevailed throughout all of human history, that was God at work, caring for His people and striving for their salvation.
Technically speaking, God is neither male nor female. We read from the Catechism:
239 By calling God "Father", the language of faith indicates two main things: that God is the first origin of everything and transcendent authority; and that he is at the same time goodness and loving care for all his children. God's parental tenderness can also be expressed by the image of motherhood, which emphasizes God's immanence, the intimacy between Creator and creature. The language of faith thus draws on the human experience of parents, who are in a way the first representatives of God for man. But this experience also tells us that human parents are fallible and can disfigure the face of fatherhood and motherhood. We ought therefore to recall that God transcends the human distinction between the sexes. He is neither man nor woman: he is God. He also transcends human fatherhood and motherhood, although he is their origin and standard: no one is father as God is Father.
370 In no way is God in man's image. He is neither man nor woman. God is pure spirit in which there is no place for the difference between the sexes. But the respective "perfections" of man and woman reflect something of the infinite perfection of God: those of a mother and those of a father and husband.
I hope that helps.