after Medusa gave birth, she handed the baby to Poseidon, because giving birth to the fruit of rape was something shameful... for her

when she abandoned the baby with Poseidon, Poseidon made a point of hiding and taking care of the baby without anyone knowing of the child's existence.

three years later, one day Aphrodite went to visit Poseidon because she had matters to resolve with him, that was when she bumped into a child, she looked surprised to see how similar this child was to Poseidon. She took the child to Olympia, where Poseidon and other gods were

Aphrodite: Poseidon... could you tell us who this child is? she said while holding the child's hand, the gods noticed the similarity between the child and Poseidon and began to distrust him.