Mrs. Doubtfire director Chris Columbus continues to explore the family turmoil of divorce in the tearjerker Stepmom, a story that pits the birth mother against the new mother. Jackie (Susan Sarandon), a one-time book editor, is now the consummate soccer mom juggling the schedules of her two kids in her New York ranch outside of Manhattan. Her ex-husband Luke (Ed Harris), who gets weekend custody of the kids, is living in the city with a woman half his age named Isabel (Julia Roberts), a high-fashion photographer with a strong stylistic sense of "what's hot." Since Luke is always away at work, the burden of getting the kids ready for school when they are with their father falls on Isabel, and she just isn't the nurturing type. The story heats up, however, when Jackie learns that she has cancer. Facing the horrors of medical tests and chemotherapy, she realizes that, should something happen to her, her kids will be left with this irresponsible Isabel as their mother, especially after Luke proposes marriage to her. What ensues is part parenting lesson, part competitive parenting, but 100 percent family bonding, as Jackie must learn to allow Isabel to be part of her world and her family.
~ Arthur Borman, All Movie Guide