Anna Nicole Smith's daughter didn't get her eye condition from her mom's drug use.

Dannielynn Hope, the late Playboy Playmate's child to Larry Birkhead, is suffering from Strabismus, which Smith's half-sister reveals is a genetic condition and not as a result of Smith's drug using during her pregnancy.

"I can confirm that it is hereditary on our father's side of the family," Donna Hogan tells OK! magazine. She says that all of their dather's children have passed along the disorder to their children. Hogan's own daughter also has the condition.

"All the doctors told me that it was more than likely genetic," Larry Birkhead has said.

Although people assumed that drugs caused the 1-year-old's eye condition, Hogan understands. "That's the first thing that goes through you mind. But as someone who knows the family history and saw the signs right away in Dannielynn, of course I knew what was going on."