Tammuz is the name of the son of Queen Semiramis of Babylon. She claimed to have an immaculate conception and that the child was King Nimrod reborn under the new name of Tammuz. This is in essence Lucifer's plan of creating his own Messiah and watering down the idea of the hero of a particular culture being born into a saving role by a virgin mother.
Jesus Christ is the only Son of God to walk the earth in human form. He faced and withstood temptation. Tammuz was simply a figure who became a Pagan icon and form of worship contrary to the Will of God.
It is the birth of Tammuz that is celebrated on December 25 every year. In subsequent years, it was noted that his birthday was only four days after the Winter Solstice, so the days were beginning to get longer and it became evident by the change in the shadows. In Pagan and Occult worship, this tribute festival to the sun was harmonized with the birth of baby Tammuz, the symbol of sin.