well, the Quran say that God has no Son and that no one earth has ever been like Him.
yet in the Gospels, Jesus identifies Himself with God in a number of unique ways, even while stating that He is distinct from the Father.
Jesus says in John 14:6-9 that if we have seen and known Him (Jesus) we have seen and known the One True God. and in John 5:23 He says that we are to honor Him just as we honor God, the Father. elsewhere, He reveals that He had glory in the Father before the world was made (John 17:5).
so for this reason, Christians identify the Lord Jesus as the second person of the Godhead. He is God, yet not all of God, as the Father still reigned in heaven while Jesus was on earth.
we say He is God's Son for a number of reasons- He is like God, and does things only God has the authority or capacity to do. He forgives sins, willfully controls the elements, gives life, and knows what is in the hearts of mn before they speak.
He is also God's Son becase He was born of the Holy Spirit, and so shares in God's qualities and nature. God begot Him into existence in history without Yosef, but by His own Spirit, will, and power.
Jesus is certainly male- He came to earth as a man of flesh and blood, and still has a glorified body today. we say this because we believe He is risen from the dead, and alive forever. Jesus calls God "Father", and teaches us to do the same.
to compare, in the Quran Allah is always translated into English in male terms, and i've never heard a Muslim refer to Allah in English as anything but "he".