Phoenix was still concerned about protecting Earth. While she loved the world and didn’t want to see it come to harm, the cosmic entity also desired to be free and unchained by responsibility. Firehair came up with a plan to convince Gaea to have an Odin-protecting child. Gaea said she wouldn’t procreate with Odin just for that reason, but the Phoenix’s pleas led her to give the Asgardian a chance. Mother Earth also noted that, if she and Odin did have a child, the Phoenix would essentially also be the baby’s mother.
Gaea and Odin ended up having a relationship and she fell in love with Thor. While she was giving birth to her son, Laufey, King Of The Frost Giants, attacked, causing the Avengers of 1,000,000 BC, to reassemble. The villain successfully frozen the infant Gods of Thunder nearly immediately after his birth, apparently killing him. Phoenix grabbed the child, and used her firepower to bring him back. Odin asked Phoenix to leave her family and she agreed. Instead, she prefered to watch Thor from far away. Phoenix, however, keeps the memories and knowledge of her child with her.
Gaea and Odin didn’t stay together particularly long. Instead, the All Father soon took Odin’s son to Asgard where Frigga raised. Thor developed a personal and close connection with the Earth as he grew up. He did this by first interacting in early human societies. Eventually, Odin sent his son to Earth to learn humility as Donald Blake, which started in earnest his journey as one of the Marvel Universe’s greatest heroes.