Some Misunderstandings About The Trinity

Christians do not believe in three Gods. The Bible says, "Hear, O Israel: The Lord our God, the Lord is one."
(The Bible, Deuteronomy chapter 6 verse 4). Christians believe in one God that is three persons.

Christians do not believe the Trinity to be God the Father, Mary and Jesus.

Christians do not believe that God had sexual relations with Mary. The Bible teaches that Mary was still a virgin when Jesus was born. "Mary asked ... 'How can I have a baby? I am a virgin.'"
(The Bible, Luke chapter 1 verse 34).

Christians do not believe Jesus is God's son in an earthly, physical sense - but that this describes his relationship with God the Father. "The Father and I are one."
(The Bible, John chapter 10 verse 30)