No, God did not "need" to have a human son. However, Jesus' human existence was necessary to redeem mankind from inherent sin, from Adam. (Romans 5:12)
To provide the ransom sacrifice, God sent one of his perfect spirit sons to the earth. But Jehovah did not send just any spirit creature. He sent the one most precious to him, his only-begotten Son. (Read 1 John 4:9, 10.) Willingly, this Son left his heavenly home. (Philippians 2:7) As we learned in the preceding chapter of this book, Jehovah performed a miracle when he transferred the life of this Son to the womb of Mary. By means of God’s holy spirit, Jesus was born as a perfect human and was not under the penalty of sin.—Luke 1:35.
How could one man serve as a ransom for many, in fact, millions of humans? Well, how did humans numbering into the millions come to be sinners in the first place? Recall that by sinning, Adam lost the precious possession of perfect human life. Hence, he could not pass it on to his offspring. Instead, he could pass on only sin and death. Jesus, whom the Bible calls “the last Adam,” had a perfect human life, and he never sinned. (1 Corinthians 15:45) In a sense, Jesus stepped into Adam’s place in order to save us. By sacrificing, or giving up, his perfect life in flawless obedience to God, Jesus paid the price for Adam’s sin. Jesus thus brought hope to Adam’s offspring.—Romans 5:19; 1 Corinthians 15:21, 22.
I continue reading more to understand the present and future benefits we can experience thanks to God's loving actions on our behalf!