There was a time when a popular book like “The Memory Keeper’s Daughter” (Penguin, 2005) by Kim Edwards – a novel that spent more than 80 weeks on national best-seller lists – would have been made into a major motion picture. But current theatrical releases seem targeted to a more youthful “chick lit” market, so “The Memory Keeper’s Daughter” (8 p.m. today, Lifetime) airs as a cable original with three movie stars, Dermot Mulroney, Gretchen Mol and Emily Watson, in leading roles.

“Memory” begins in 1964, when Dr. David Henry (Mulroney) helps deliver his wife, Norah’s (Mol), twins. When he realizes that the female twin is a Down syndrome child, he is flooded with bad memories of how his “simple-minded” and sickly sister drained his mother’s strength and ruined his poor family’s happiness.

He impetuously asks his nurse, Caroline (Watson), to secretly deliver the child to a local home where such infants have been consigned. When Norah revives, he tells her that their second child has died.

Repulsed by the squalid nature of the home and shocked by David’s deception, Caroline soon leaves town to raise the baby on her own. “Memory” follows the two families as the children grow over the next two decades.

There’s nothing like a foundling child or a baby switched at birth to supercharge a plot with a primal emotional wallop. It’s a story at least as old as Moses. But the film version soon settles into well-worn grooves familiar to fans of any potboiler.

This could be better.

¢ Elizabeth Vargas hosts “Human Footprint” (8 p.m. Sunday, National Geographic), an ambitious special that spells out, in graphic terms, the environmental impact of Americans’ eating and buying habits.

Figuring that an average American lives slightly more than 77 years, it uses a flood of rubber ducks flowing down the stairs of a house and out into the street to represent the 28,433 showers we will take in our span. We also see 13,056 pints of milk, 87,520 slices of bread (make mine whole wheat!), 43,371 soda cans (diet, please!) and a 50-foot wall of old appliances. (So that’s where my old Kaypro computer went.)

And we haven’t even gotten to the part about the cars of our lives and the oil and gas we need to fuel them. It’s a serious look at how we live, with the goal of raising awareness about the little mess we leave behind and how those collective piles are turning the planet into an ashtray.

Today’s highlights

¢ Jai Rodriguez (“Queer Eye for the Straight Guy”) hosts “Groomer Has It” (8 p.m., Animal Planet), a weekly competition between America’s 13 best dog stylists..

¢ An explosion results in revealing flashbacks on “Torchwood” (8 p.m., BBC America).

¢ Ashton Kutcher hosts “Saturday Night Live” (10:30 p.m., NBC), featuring musical guest Gnarls Barkley.

Sunday’s highlights

¢ Gender roles and expectations on “Nature” (7 p.m., PBS, check local listings).

¢ Candidates Barack Obama and Hillary Clinton discuss faith (7 p.m., CNN).

¢ Jon Stewart hosts “Night of Too Many Stars” (7 p.m., Comedy Central), a benefit concert for autism education.

¢ Adams wrestles with the Alien and Sedition Acts and his son’s wayward ways on “John Adams” (8 p.m., HBO, part 6 of 7).