It isn’t just this summer: dead mothers provided the plot point for “Sleepless in Seattle,” “My Girl” and as far back as “Bambi.” The heroine’s mom is presumed dead in Disney’s “Aladdin,” “Beauty and the Beast” and “The Little Mermaid.” On TV, dads have fumbled to raise kids on their own since the 1950s. Remember “Bachelor Father,” “Gidget” and “My Three Sons”? Hope Edelman, author of “Motherless Daughters,” counted 50 motherless-families series since the dawn of television; one study found that TV families are seven times more likely to have a dead mother than those in real life. This fall, widowed fathers return in “Full House” and “The Nanny.” They’ll be joined by ABC’s “Me and the Boys” and NBC’s “Earth 2,” which features a single dad in outer space.

All this morbidity taps a deep psychological nerve. In his 1976 book, “The Uses of Enchantment,” Bruno Bettelheim argued that fairy tales like “Snow White” and “Cinderella” have endured precisely because they confront children’s subconscious fears – and show how they must conquer separation anxiety to live happily ever after. It’s also a handy plot device: coming of age is always more exciting when mom can’t protect you. “You can’t have mom and danger at the same time,” says Betsy Stone, a Stamford, Conn., psychologist and mother.

Does so much exposure to maternal death breed unrealistic fears? Some experts argue that such stories help build resilience. “When parents go to extraordinary lengths to protect children from small doses of adversity and loss, they grow up without the capacity to bounce back when it happens to them head-on,” says Harvard child psychiatrist Dr. John Livingstone. But others disagree. “Young children aren’t ready to handle such material – it just scares the hell out of them,” says Jerome Singer, a child psychologist at Yale. Stone says you could extend Bettelheim’s logic “and take kids to see movies with explicit sex, so they can work through their feelings.” But few parents would. “There are a lot of things that kids have to deal with in life that they don’t have to deal with right now.”

What message kids take away from movies is also highly unpredictable; a tiny detail may surface as a nightmare later on. Much depends on the surrounding material. In “Angels in the Outfield,” the hero relies on “magical thinking” – his appeal to God to aid the hapless team – but it’s the wise foster mother who helps him handle his loss. Jessie Nelson, who wrote and directed “Corrina, Corrina,” lost her own mother when she was 3, and wanted her father to marry their aged black maid. Yet it was Whoopi Goldberg who suggested the line “You’ll always miss your mother, and that’s OK.” Experts say it’s critical to remember the deceased – but in most scripts, the characters don’t. “I call it the “Bonanza syndrome,’ says Edelman. “That father had lost three wives – and rarely was any of them discussed.” Edelman also says many motherless-family stories – from “Nanny and the Professor” to “The Sound of Music” – raise the romantic notion that a substitute mom will make the family whole again. “In reality, that rarely happens.”

Should parents avoid movies with morbid underpinnings? Singer says 8-, 9- and 10-year-olds should be able to “tell the difference between reality and fantasy. It’s the 3-, 4- and 5-year-olds who may be overwhelmed.” And parents should talk to their kids about what they see on screen. But if anyone thinks it’s tough to discuss a mom’s death, just think about explaining the movie “Junior,” coming out later this year, in which Arnold Schwarzenegger gets pregnant. That may be carrying the who-needs-mom motif one step too far.