A Star of David tattoo would most likely be worn by a younger-generation Jew, especially of a less-strict sect, such as Conservative or Reform. The Star of David is a modern Jewish symbol. The Torah prohibits tattooing, but many modern Jews question this teaching.
The Magen David, "shield of David," or Star of David is supposed to represent either the shape of or the emblem on King David's shield. It is a relatively new symbol that has come to represent the Jewish faith.
In Leviticus 19:28, the Torah states "You shall not make gashes in your flesh for the dead, or incise any marks on yourselves: I am the Lord." From the second part of this, Judaic teachings derive the prohibition against tattooing. Notable rabbi Simeon ben Judah disagrees, saying a tattoo is not a culpable act unless it includes the name of G-d. The Babylonian Talmud also debates the issue. Professor Aaron Demsky of BarIlan University suggests that non-idolatrous tattooing may have been permitted in biblical times. He cites Isaiah 44:5 "[One] shall mark his arm 'of the Lord' and adopt the name of Israel," and Isaiah 49:16, "See, I have engraved You on the palms of my hands." Many younger Conservative and Reform Jews agree with Simeon ben Judah and Aaron Demsky.