PRIVATE PRACTICE - "Apron Strings" - In this Addison-centric episode, her role as a parent is challenged when Henry's biological mother reappears and asks to be more involved in her young son's life. Meanwhile Addison reconnects with her mentor, who shares a very painful secret, on "Private Practice," TUESDAY, NOVEMBER 20 (10:00-11:00 p.m., ET) on the ABC Television Network. (ABC/RANDY HOLMES) GRIFFIN GLUCK, KADEE STRICKLAND, PAUL ADELSTEIN