America’s next generation of youngsters should be called “Generation Rex.”

If you’re wondering why playgrounds around the city are so quiet and dog runs are packed, a new report has an answer: More and more US women are forgoing motherhood and getting their maternal kicks by owning handbag-size canines.

Data from the Centers for Disease Control and Prevention show that a big drop in the number of babies born to women ages 15 to 29 corresponds with a huge increase in the number of tiny pooches owned by young US women, reports the business-news site Quartz.

Dog-crazy New York ladies told The Post that they aren’t surprised by the findings — and that they happily gave up diaper changes, temper tantrums and college funds for the easy affection of their doggy “child.”

“I’d rather have a dog over a kid,” declared Sara Foster, 30, a Chelsea equities trader who says her French bulldog, Maddie, brings her more joy than a child.

“It’s just less work and, honestly, I have more time to go out. You . . . don’t have to get a baby sitter.”

The federal data behind the report show that over the past seven years, the number of live births per 1,000 women between ages 15 and 29 in America has plunged 9 percent.

At the same time, research by the American Pet Products Association shows the number of small dogs — under 25 pounds — in the United States has skyrocketed, from 34. 1 million in 2008 to 40.8 million in 2012.

“Women are not only having fewer children but are also getting married later. There are more single and unmarried women in their late 20s and early 30s, which also happens to be the demographic that buys the most small dogs,” market researcher Damian Shore told Quartz.

Asked if he thought the drop in baby births and the rise in puppy ownership was a coincidence or if women these days were really making dogs their little bundles of joy, Shore said, “There’s definitely some replacement happening there.”

Dog lovers interviewed by The Post said the trend has long been going on in the city, where single women with pocket pooches have been a standard for years.

Mary Smith, 25, of Murray Hill, said her 6-month-old French bulldog, Toliver, brings her as much joy as a baby would.

“Dogs are better! Look at Toliver! He’s great, except he snores a lot. He even has his own Instagram,” Smith said during a walk with the pooch. “A dog is easier to transport than a child. It’s less final than having a child.”