Mackenzie Phillips' half-sister claims their father never made sexual advances towards her -- even though Mack supposedly had an incestuous 10-year relationship with the guy.
Chynna defended her sister today on Oprah -- where she said she absolutely believes the "hideous" allegations Mackenzie made about their dad, Mamas and the Papas singer John Phillips.
Mackenzie's Sis -- Dad Never Made a Move on Me
9/25/2009 6:00 PM PDT BY TMZ STAFF
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