Episode 7, Lineage

A woman named Rachael Dunleavy shows up claiming to be Clark's biological mother, and that Lionel was his biological father. Clark dismisses her claims, but Rachael files a court order to have a DNA test performed. Clark and Pete sneak into the testing labs, and Clark swaps Pete's DNA for his so that the technicians do not figure out that he is not human. When the results come back negative, Rachael kidnaps Lex in an effort to force Lionel to admit that he fathered a child with her and that Clark is their son. Rachel witnesses Clark using his abilities when he rescues Lex and realizes that he is not her son. Lionel later admits to Lex that he did father another child, but that it died as an infant. Later, Lionel is seen with a locket and a picture of a young boy. Meanwhile, Lana finds the man from the photo, Henry Small, who eventually agrees to do a DNA test to determine if he is her father. 

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