THE PARENTS: MarCedes Carter, 39, and William Carter, 38, of Clifton Heights

THE KIDS: Keaton McKinley, 6; Peyton Meila, 4; Braxton William, born April 17, 2017

THE BEAUTY OF A PLANNED C-SECTION: The couple dropped off the girls at daycare, then headed to Einstein Medical Center Montgomery; Braxton was born in time for William to make it back to pick up the girls.

Five-year-old Keaton patted her mother's stomach and declared, "Mommy, you have a baby in your belly."

"No," MarCedes answered. "I just need to lose a little weight."

But Keaton repeated the announcement a few days later. Then a third time. "I thought: This kid knows something," MarCedes recalls. "I bought the test, then forgot about it for a day. Lo and behold, it was positive. That blew my mind."

It wasn't the first time the couple felt stunned by a pregnancy. MarCedes wasn't supposed to be able to conceive — not, at least, according to a doctor who examined her when she was in her early 20s and complaining of irregular periods.

"I don't know that I really felt the weight of it until I met William, and I knew I wanted to have this life with him," she says. They met while working at different Blockbuster stores; they spotted each other at a meeting of regional managers, but William needed some persuasion to break his "never date a colleague" rule.

"I was smitten with him right away," MarCedes says, even when he kept her waiting for more than 30 minutes before their first date. It took a three-day snowstorm — they were housebound at MarCedes' place in North Philly — to convince William that she was the one. He moved in with her; later, they got an apartment of their own while both shifted from retail work into banking.

They'd been together for about a year when MarCedes confided her doctor's grim prognosis. "I was scared," she remembers. "I didn't know how he was going to take it. He was very sweet about it — reassuring, loving. He said he felt like I would be the mother of his children, but I never believed it."

They crossed other thresholds: an engagement, when William first teased her with a handmade paper ring before proffering the real thing, a simple band inscribed "Love you forever." Then a house. Marriage came in 2009, a ceremony both remember for the giggling fit that seized them as they recited their vows.

"We got married, bought a home; our careers were fully established. I knew how important it was to her to start a family. This was the missing link," William says.

They tried for nearly seven years: three fertility doctors, a diagnosis of polycystic ovarian syndrome, one ovarian surgery, countless hormone injections that only added to MarCedes' emotional maelstrom.

"I thought if I just kept doing one more thing, tried a little differently, something might happen," she says. They drew the line at IVF after a fertility specialist counseled that the limited odds wouldn't be worth the cost. They began to consider adoption, then balked when they realized it was no guarantee; they might invest emotion and money only to have a birth mother change her mind.

Then William learned of a homeopathic medicine that was supposed to help regulate hormones. It looked like clay, MarCedes says, and tasted like dirt, but she swallowed it anyway. She took Pilates classes, followed the South Beach diet, and tried to relax.

It was February 2011 when a nagging fatigue prompted her to stop at a CVS MinuteClinic during a break from work.

"I peed on the stick … then the lady said, 'You're pregnant!' I said, 'No, I'm not. Can I see that?' I didn't believe it. I said, 'I've been trying for years.' "

When she finally reached William — he was in a managers' meeting at work — he was speechless. They phoned family members. MarCedes ate a baked potato with sour cream and butter. And William quickly shifted into "super-protective mode, making sure she didn't so much as get a paper cut."

After years of fertility treatment, pregnancy felt almost underwhelming: no morning sickness, no medical crises. But labor was a 40-hour ordeal of erratic contractions, an epidural, and, finally, a C-section. MarCedes remembers her surprise when the doctor announced the baby was a girl; William recalls surges of excitement and relief. "We've made it through. We actually do have a child in the family."

Seven months later, MarCedes was shopping for a bathing suit for a Mother's Day weekend at the beach with friends. "I thought, 'I still look pregnant.' " When the test she took at work turned out positive, "I almost had a nervous breakdown. I started crying; I was beside myself."

Peyton — named to chime with her sister, with six letters ending in "ton" — arrived after a "fast and furious" 12-hour labor and a C-section once again because the baby was breech. And though it was hectic having two babies in diapers, the house was child-proofed, the girls as intimate as twins, their parents already keen to the rhythms of infancy.

"There was no doubt in my mind that our family was complete," William says. And then, just as the two were anticipating the elementary school years and adjusting to new jobs a bit closer to home, MarCedes listened to her older daughter, took that test, and called her husband at work to say, for the unbelievable third time, "I'm pregnant." They chose the name Braxton — another "ton" ending — for their son.

There are moments, MarCedes says, when all three kids need her at once: One is pleading for juice; the other fell and wants a kiss; the baby's wailing because he's hungry. "In that moment, I panic. But they all have to wait for somebody else now; they can't be first all the time."

For William, their life is the curveball no one saw coming. "You think life's going in a certain direction; you feel like you can manage everything. I did foresee a family, but I never thought MarCedes and I would have three children under the age of 6."

He can't wait until they're all old enough to hear the story: How their parents imagined their existence but didn't quite believe it; how each of them was an astonishment, a sweet surprise.