Adam was created in God’s image but when Seth was born, he was made in the image of his sinful and fallen father, Adam, not in the image of God.
Genesis 5: 3 Adam was 130 years old when he fathered a son in his likeness, according to his image, and named him Seth.
Adam was created a triune being, Body, soul and spirit. When he sinned, his spirit died and he became a dual being, body and soul. Seth and every human being since, has been born a dual being. That is why Jesus said that we must be born again.
John 3: 5 Jesus answered, “I assure you: Unless someone is born of water and the Spirit, he cannot enter the kingdom of God. 6 Whatever is born of the flesh is flesh, and whatever is born of the Spirit is spirit.
Do not let anyone tell you, “We are all children of God”, that is a lie. Do not let anyone say, “We are all created in the image of God”, that is a lie. We are all children of Adam, we have all descended from Noah, but only those who have been born of the Spirit are Children of God.