The logical fallacy of No True Scotsman occurs when someone tries to place artificial limits on what will be accepted as a true statement.
Sandy: "No scientist believes in creation."
Rocky: "Well, Werner Gitt is a scientist and he believes in creation."
Sandy: "He obviously doesn’t count as a true scientist because he believes in creation. No true scientist believes in creation."
Rocky: "There are thousands of scientists like Werner Gitt who don't accept the Big-Bang-Billions-of-Years-No-Flood-Molecules-to-Man story and are doing important work in science."
Sandy: "They aren't real scientists then."
Sandy: "Creationists don't publish in peer reviewed scientific journals."
Rocky: "That's not true. Creation scientists publish in both the standard secular scientific journals along with peer reviewed scientific journals that don't presuppose the atheistic worldviews of naturalism and materialism."
Sandy: "Those journals that don't demand naturalism and materialism as a prerequisite are not real scientific journals. And just because the creationists can sometimes get an article into the REAL scientific journals, they have to do it by not writing anything about God, creation, or any such thing. So, my statement stands. Creationists don't publish, as creationists, in the REAL peer reviewed scientific journals."