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(Holy Bible ) Mathews chapter 1 verse 16 says and Jacob begat (gave birth) Joseph the HUSBAND of Mary, of WHOM was born Jesus, who is called Christ. Further in verse 25 states and he(Joseph) knew her not (ie no physical relation) till she had brought forth her firstborn son and he called his name Jesus. So it is clear that Joseph was not father of Jesus and further as stated he knew her not (Mary). Verse 18 says now the birth of Jesus Christ was on this wise. When as his mother was espoused(engaged) to Joseph, before they came together (physical relation) she was found with child of the Holy Ghost.(ghost means atma) . so in worldly/ understanding he was called the father of Jesus but was born of HOLY GHOST.