“But when the fulness of the time was come, God sent forth his Son, made of a woman, made under the law,” (Galatians 4:4)
Jesus was the first child of Mary and Joseph. Even though he was not their genetic and biological son, they considered him their very own son and raised him. Jesus became truly a human. He was not just in human form, but in every detail a human. The virgin birth allowed him to be 100% human.
But Jesus was also 100% God. Although Jesus was born human, the virgin birth spared him from inheriting the sinful nature of man. Also, the fact that Mary conceived through the work of the Holy Spirit preserved the divinity of Jesus. So even if Jesus was born human, he was still the Son of God – the only begotten Son of the living God. The angel Gabriel told Mary, “The Holy Spirit will come down to you, and God’s power will come over you. So your child will be called the holy Son of God.”