For much of the 20th century, Norman Rockwell's Freedom From Want served as the portrait of the idealized American family. Here are three generations gathered around the dinner table as a smiling grandma presents her spawn and theirs with a roast turkey as big as a Buick.

If Rockwell were alive today, when there's a smorgasbord of options for building a clan, his picture of the American brood might resemble the post-nuclear family of The Kids Are All Right, Lisa Cholodenko's comedy opening Friday. Here are two lesbian mothers, their two teenagers - each the offspring of one of them - and the sperm-donor dad gathered around the picnic table, getting to know each other over burgers and chips 18 years after bio-dad's deposit at the sperm bank.

With Annette Bening and Julianne Moore as "the Moms," supremely straight in their gayness, and Mark Ruffalo as "Sperm Dad," nonconformist and noncommittal in his straightness, The Kids Are All Right is one of a clutch of recent films repainting the portrait of the American family. However imaginative some of the plots may be, academics and demographers agree that they represent America's evolving social arrangements.

In other words, what's bringing together the American family is no longer the turkey but the baster.

Among the others:

The Back-up Plan, a slapstick comedy with Jennifer Lopez as a single woman who has a successful insemination the very day she meets the perfect man, whom she dates during pregnancy.

Splice, a black-comic horror flick with Adrien Brody and Sarah Polley as cohabiting genetic researchers who disagree about having kids (he wants, she doesn't) but who nonetheless become parents to a human/animal hybrid she creates using her own DNA.

The Switch (original title The Baster, and due Aug. 20), with Jennifer Aniston as the single woman who gets pregnant with donor sperm without realizing that her platonic friend (Jason Bateman) substituted his stuff for that of the anonymous donor.

"The family has changed so dramatically and so rapidly over the last 50 years that it's almost unrecognizable," says Elaine Tyler May, an American studies professor at the University of Minnesota and the author of America and the Pill. "These films are grappling with something that's come very rapidly into the American consciousness."

Stephanie Coontz, author of Marriage: A History, adds, "What we're seeing on-screen reflects a perfect storm of new possibilities and new complications.

"Obviously, several things are going on in the culture that are reflected in these movies," she notes. Those things include new technologies available to form a family and wider acceptance of nontraditional family units like domestic partnerships and single parenthood.

"Today, a baby can have five different parents - two biological parents, a surrogate mother, and also a social [adoptive] mom and pop," Coontz says.

That's pretty rich material for either comedy or drama. The quest to find one's parents is at least as old as Telemachus searching for Odysseus.

These new movies - "films about new family formations," May calls them - reflect other cultural shifts.

Marriage and parenthood have become increasingly decoupled. The proportion of births to nonmarried couples is on the rise. According to a 2007 survey conducted by the Pew Research Center, "today about half of all nonmarital births are to a cohabiting couple; 15 years ago only a third were."

In view of these figures, a question implicitly raised by the domestic partners in The Kids Are All Right is: How many of those cohabiting couples would be wed if gay marriage were legal in all 50 states? The specifics of same-sex marriage aren't debated in the movie about the universals of parent/child relations.

"It's as though in films and television, we've gone from 'gays and lesbians aren't parents' to 'gays and lesbians are parents like everyone else' without much discussion of the process - outside of public policy debates," says Gary Gates, a demographer at the Williams Institute, a think tank on sexual orientation law at the University of California, Los Angeles.

Cholodenko agrees. "I think what I've done is to make the issues nonissues," she says. Her film focuses on the drama of spousedom and parenthood rather than on the politics of gay marriage. "The film was born from the personal experience of my partner [musician Wendy Melvoin] and I wanting to have a family and projecting into the future." (They are mothers to a 4-year-old son.)

From the conception of The Kids Are All Right to delivery, public attitudes toward gay marriage and domestic partnerships shifted.

"The timing is fortuitous," says Cholodenko. According to a Gallup Poll in 2006, when her son was born, 42 percent of Americans approved of gay marriage. In May 2010, the approval figure was 44 percent. "When you substitute 'legal rights for domestic partners' for 'marriage,' " Gates says, "in 2010 the approval rate is 60 percent."

With the exception of Splice, where the man is the one with baby fever, the films repainting the picture of the American family begin as stories of how parenthood is more urgent for the female character(s) than for the male. This trend reflects 2010 figures from the Washington-based Population Research Bureau: 24 percent of America's 75 million children under 18 live in single-mother families.

With the exception of The Kids Are All Right, where it is implied, this batch of new-American family films is overwhelmingly about women who take procreation into their own hands. In the '70s of Looking for Mr. Goodbar, movies purveyed anonymous sex; today, in the era of The Switch, they purvey anonymous sperm.

Used to be, first comes love, then marriage and baby carriage. Now it's first comes sperm, then comes baby. As A.O. Scott of the New York Times observed this month, "The childishness of grown men and the childlessness of grown women [have become] the twin axioms of big-screen comedy."

Despite the nontraditional clans represented, says the University of Minnesota's May, "it's interesting how all these films are pro-family, and how the bonds of love and care are affirmed."

In other words, the more things change, the more the challenges of couplehood, parenting, and family life remain the same. What's for dinner?